HK1111377A - Molten metal molding machine - Google Patents

Description

Molten metal forming apparatus

Technical Field

The present invention relates to a molten metal molding apparatus for injecting and filling a molten metal (molten metal solution) into a mold cavity, and more particularly to a molten metal molding apparatus including a metal melting mechanism for melting a metal material in a heating cylinder.

Background

As a molten metal molding apparatus for obtaining a product by injecting and filling a molten metal material into a mold cavity, there is known a cold chamber die casting machine which includes a melting furnace (crucible) for melting a metal material (for example, Al alloy, Mg alloy, or the like), measures and draws up the metal material melted by the melting furnace in a barrel amount per shot, injects the drawn-up molten metal (molten metal solution) into an injection tube, and injects and fills the molten metal into the mold cavity by high-speed forward movement of an injection plunger. In this cold chamber type molten metal molding apparatus (die casting machine), since a metal material (molten metal) melted by a melting furnace is drawn up by a barrel and conveyed, the entire apparatus becomes a large-sized apparatus, and when the metal material is drawn up by the barrel and conveyed, the surface of the molten metal in contact with air is oxidized or the temperature is lowered, and there is a limit to improvement in product quality.

Then, a molten metal molding apparatus has been proposed in which a molten metal material is melted by a heating cylinder also serving as a syringe without using a melting furnace for melting the metal material (see patent document 1: Japanese patent application laid-open No. 2004-148391).

Fig. 7 is an explanatory diagram showing a molten metal molding apparatus having substantially the same configuration as the technique described in patent document 1. In fig. 7, 101 denotes a heating cylinder, 102 denotes a nozzle (hot runner nozzle) provided at the front end of the heating cylinder 101, 103 denotes a band heater wound around the outer periphery of the heating cylinder 101 and the outer periphery of the nozzle 102, 104 denotes an inner cavity molded by a mold (not shown) and communicating with the front end of the nozzle 103, 105 denotes an oxide film peeling section (mold) provided at the rear end of the heating cylinder 101, 106 denotes an on-off valve provided at a position near the rear end of the heating cylinder 101 and communicating the inside of the heating cylinder 101 with a vacuum pump 107 when assuming an open position, 107 denotes a vacuum pump communicating with a hollow portion in the on-off valve 106 and evacuating the inside of the heating cylinder 101 (a state close to vacuum), 108 denotes a gauge for checking the degree of vacuum in the heating cylinder 101, 109 denotes an air source, 110 denotes an electromagnetic valve for controlling the on-off valve 106 by air pressure from the air source 109, 111 denotes a material receiving section disposed opposite to the opening of the rear end of the heating cylinder 101, reference numeral 112 denotes a piston body which is driven by a hydraulic cylinder, not shown, and can advance and retreat in the material receiving portion 111 and the heating cylinder 101.

In the configuration shown in fig. 7, as shown in fig. 7(a), first, the preheated cylindrical metal materials 113 of a predetermined length are dropped and supplied one by one into the material receiving section 111 from a preheating device (not shown) provided above the material receiving section 111 and accommodating the cylindrical metal materials 113 of a predetermined length in one vertical direction. At this time, the metal material 113 pressed into the heating cylinder 101 in advance by the piston body 112 is filled by a predetermined amount from the front end side in the heating cylinder 101 and the nozzle 102, and the metal material 113 is gradually melted as it advances from the position closer to the rear end in the heating cylinder 101 to the nozzle 102, and the metal material 113 is completely melted in the nozzle 102. In addition, the on-off valve 106 is in a locked state at this time.

Next, as shown in fig. 7(b), the piston body 112 is advanced at a low speed, the metal material 113 is pushed from the material receiving portion 111 to the rear end side of the heating cylinder 101, and the oxide film on the outer periphery of the metal material 113 is peeled off by the oxide film peeling portion 105 at the time of this pushing. When a part of the metal material 113 enters the heating cylinder 101 from the material receiving portion 111, the opening at the rear end of the heating cylinder 101 is closed by the metal material 113, and therefore, the advance of the piston body 112 is temporarily stopped in this state. Then, the switching valve 106 is switched to the open position by the electromagnetic valve 110, the inside of the heating cylinder 101 is communicated with the vacuum pump 107, and the inside of the heating cylinder 101 is evacuated by the vacuum pump 107.

After the inside of the heating cylinder 101 is evacuated, as shown in fig. 7(c), the switching valve 106 is switched to the closed position by the electromagnetic valve 110, and then the piston body 112 is advanced at a high speed. As a result, the metal material 113 that has been pushed by the piston body 112 and reloaded into the heating cylinder 101 sequentially pushes the metal material 113 to the front side, and by this pushing, as shown in fig. 7(d), the molten metal material (molten metal solution) 113 in the nozzle 102 starts to be rapidly injected into the cavity 104.

Then, as shown in fig. 7(e), when the metal material 113 completely extends into the cavity 104 and injection (injection, filling) is completed, the pressure applied to the piston body 112 from the metal material 113 rises to a predetermined value, and the advance of the piston body 112 is stopped when the pressure is detected.

When the injection of the metal material 113 into the cavity 104 is completed, the metal material 113 in the cavity 104 is rapidly cooled and solidified by extracting heat from the mold. In this cooling step, the heating control by the tape heater 103 wound around the nozzle 102 is interrupted, whereby the metal material 113 on the tip side in the nozzle 102 is also cooled and solidified, and the tip side of the nozzle 102 is sealed (closed) by the solidified metal material 113. After the injection is completed, as shown in fig. 7(f), the piston body 112 is driven to retreat to a position where it can drop to the receiving portion 111 and supply a new metal material 113. After the cooling and solidifying steps are completed, the mold is opened, and the solidified product (casting) is cut off from the metal material on the nozzle 102 side (in this case, the nozzle 102 is heated before the mold is opened for easy cutting), and is integrated with a movable mold (not shown) and separated from a fixed mold (not shown). After the end of the mold opening or during the mold opening, the product is released from the movable mold by a pushing mechanism not shown and taken out by a robot not shown.

In the molten metal molding apparatus shown in fig. 7, since the heating cylinder 101 serving also as a syringe is used to melt the metal material and the molten metal (molten metal solution) is directly injected and filled into the cavity of the mold from the nozzle 102 at the front end of the heating cylinder, a large melting furnace is not required, and the entire apparatus can be assembled in a relatively compact manner, as compared with a cold chamber die casting machine having a melting furnace in which the metal material melted in the melting furnace is metered and drawn up into a barrel in the amount of material to be injected each time and then injected into the syringe. Further, since the molten metal is less likely to contact air, the molten metal is less likely to be oxidized.

However, in the molten metal apparatus shown in fig. 7, if the diameter of the ridge surface of the nozzle 102 at the distal end of the heating cylinder 101 is not set to be smaller than a certain level, the response of melting or solidification of the metal material 113 of the nozzle 102 is deteriorated, and therefore, the diameter of the ridge surface of the nozzle 102 must be set to be smaller than a certain level. However, if the diameter of the land surface of the nozzle 102 is small, the following problem occurs. That is, in the injection and filling of the molten metal, it is generally considered that the molten metal passing speed at the gate portion or the runner portion of the mold is set to 55 m/sec or less, preferably 30 to 40 m/sec, in view of sand sticking and pressure loss. The throughput of molten metal per unit time is the product of the area of the diameter of the land of the nozzle 102 and the passing speed, and since the diameter of the land of the nozzle 102 is small and there is a limitation in the passing speed as described above, the throughput of molten metal per unit time, in other words, the filling amount is naturally limited. In the molding of the molten metal, since the molten metal is rapidly cooled and solidified after being filled into the cavity as described above, the filling time is generally as short as about 0.1 to 0.05 seconds. From the above, the molten metal molding apparatus shown in fig. 7 is also naturally limited in the weight of the product that can be molded (cast) no matter how sufficient the melting ability of the metal is.

In this regard, the cold chamber die casting machine (molten metal molding apparatus) is excellent in versatility because it can set an optimum injection/filling speed or a size of a passage area of a molten material path for each product.

Thus, the applicant of the present invention proposed a molten metal molding apparatus having the following advantages in Japanese patent application No. 2005-223038: the melting furnace is not used when the metal material is melted, but the advantage of the structure that the metal material is melted by the heating cylinder is utilized; and the advantages of the cold chamber die casting machine. In the molten metal molding apparatus proposed in this japanese patent application No. 2005-223038, a molten metal is supplied by dropping and supplying a molten metal into a cylinder from a nozzle portion provided on the distal end side of a heating cylinder, and the molten metal supplied into the cylinder is injected and filled into a mold by an injection plunger, thereby realizing a molten metal molding apparatus having both the advantages of a structure in which a metal material is melted by a heating cylinder and the advantages of a cold chamber die casting machine.

However, in the molten metal molding apparatus proposed in the above-mentioned japanese patent application No. 2005-223038 or the molten metal molding apparatus described in the above-mentioned patent document 1, since the degree of pressing of the preheated cylindrical metal material into the heating cylinder is variably controlled in accordance with the amount of filling of the molten metal into the mold, when the amount of filling of the molten metal into the mold is small, the reloaded (inserted) metal material cannot be completely pressed into the heating cylinder, and there is a problem that a part of the metal material is exposed to the air for a long period of time and is seriously oxidized, or a part of the metal material is exposed to the air for a long period of time and the temperature is lowered. In the molten metal molding apparatus proposed in japanese patent application No. 2005-223038 or the molten metal molding apparatus described in patent document 1, the amount of molten metal to be filled into the mold is limited to the amount of one cylindrical metal material or less, and it is not considered that the amount of molten metal to be filled into the mold is set to an amount exceeding the amount.

In view of the above, the present applicant has proposed in japanese patent application No. 200-372677 a molten metal molding apparatus having a structure in which a molten metal material is melted by a heating cylinder without using a melting furnace when melting the metal material, wherein even when the amount of the molten metal to be filled into a mold is small, a trouble that a part of the metal material to be refilled is exposed to the air for a long period of time does not occur, and the amount of the molten metal to be filled into the mold can be set to more than one cylindrical metal material.

However, the molten metal molding apparatus described in patent documents 1, 2005-223038, and 2005-372677 has a structure in which oxide film peeling portions formed of molds are provided at both ends of a heating cylinder. This is because the oxide film is supposed to be present on the outer periphery of the columnar metal material, but if the columnar metal material is taken out one by a robot from a preheating device held by an inert gas medium and is rapidly and completely pressed into the heating cylinder, there is practically no possibility that the columnar metal material is oxidized. However, if the oxide film peeling section formed by the mold is provided on the rear end side of the heating cylinder as described above, (1) the speed of pushing the cylindrical metal material into the heating cylinder cannot be increased, (2) the oxide film peeling section is worn and needs to be replaced, and (3) in order to avoid the cutting of the front end cylindrical portion of the straight moving body that can be pushed into the heating cylinder by the oxide film peeling section, a gap is provided between the outer periphery of the front end cylindrical portion of the straight moving body and the inner periphery of the heating cylinder, and therefore, there is a problem that the rear end side of the heating cylinder cannot be sealed from the outside air by the front end cylindrical portion of the straight moving body.

Disclosure of Invention

The present invention has been made in view of the above problems, and an object of the present invention is to solve the problems caused by the presence of a mold by configuring a structure in which an oxide film peeling section (mold) is removed on the rear end side of a heating cylinder in a molten metal molding apparatus having the advantages of the above-mentioned japanese patent applications 2005-223038 and 2005-372677.

In order to achieve the above object, a molten metal forming apparatus according to the present invention is a molten metal forming apparatus in which a preheated columnar metal material is sequentially supplied into a heating cylinder from a rear end side of the heating cylinder, the metal material is sequentially pressed into a front end side of the heating cylinder by a linear motion body, the metal material is gradually melted as the metal material moves from the rear end side to the front end side of the heating cylinder by heating by a heater attached to the heating cylinder, and the outer periphery of a front end cylindrical portion of the linear motion body which can be pressed into the heating cylinder is made to slide with respect to the inner periphery of the heating cylinder with a predetermined amount of clearance between the inner periphery of the heating cylinder and the outer periphery of the columnar metal material, and a new metal material can be completely pressed into the heating cylinder regardless of a filling amount into a mold.

In addition, the front end cylindrical portion of the straight moving body is positioned in the heating cylinder except when a new metal material having a cylindrical shape is supplied into the heating cylinder.

Further, the inside of the rear end side of the heating cylinder is kept in an inert gas atmosphere.

The molten metal is supplied by dropping and supplying the molten metal into the cylinder from a nozzle portion provided at the distal end side of the heating cylinder, and the molten metal supplied into the cylinder is injected and filled into the mold by an injection plunger.

Further, the stroke of pushing the straight body for supplying the molten metal may be set to be longer than the entire length of one of the columnar metal materials.

The present invention has the following effects.

In the molten metal forming apparatus according to the present invention, the gap of a predetermined amount is provided between the inner periphery of the heating cylinder and the outer periphery of the columnar metal material, and the outer periphery of the front end columnar portion of the straight body that can be press-fitted into the heating cylinder can be slid with respect to the inner periphery of the heating cylinder, so that the new columnar metal material can be completely press-fitted into the heating cylinder regardless of the amount of filling into the mold. Therefore, when the columnar metal material is pressed into the heating cylinder, as in the prior art, a large resistance is not generated when the columnar metal material enters the heating cylinder, so that the columnar metal material can be smoothly pressed into the heating cylinder at a high speed, the pressing speed can be improved, and even when the filling amount of the molten metal in the mold is small, a defect that a part of the metal material to be refilled is exposed to the air for a long time as in the prior art is not generated, so that the possibility of oxidation of the new metal material can be reduced as much as possible, and the possibility of temperature reduction of the new metal material is not generated. Further, since there is substantially no gap between the inner periphery of the heating cylinder and the outer periphery of the front end cylindrical portion of the linear motion body, the front end cylindrical portion of the linear motion body is positioned in the heating cylinder in addition to the supply of the new cylindrical metal material, and the rear end side of the heating cylinder can be sealed from the outside air by the front end cylindrical portion of the linear motion body, so that the oxidation of the metal material in the heating cylinder can be suppressed as much as possible. Further, since the reloaded metal material can be completely pushed into the rear side of the heating cylinder in which the inert gas atmosphere is maintained, by doing so, the possibility of oxidation of the metal material pushed into the heating cylinder can be eliminated. Further, in the molten metal molding apparatus having both the advantages of the structure in which the molten metal material is melted by the heating cylinder without using the melting furnace and the advantages of the cold chamber die casting machine, since the press-in stroke of the linear actuator for supplying the molten metal can be set longer than the entire length of the one columnar metal material, it is possible to easily mold a large-sized product having an increased weight in which the amount of the molten metal to be filled into the mold exceeds the amount of the one columnar metal material, as in the above-mentioned japanese patent application No. 2005-372677.

Drawings

Fig. 1 is a simplified explanatory view showing a main part of a molten metal molding apparatus according to an embodiment of the present invention.

Fig. 2 is a simplified explanatory view showing a main part of a molten metal molding apparatus according to an embodiment of the present invention.

Fig. 3 is a simplified explanatory view showing a main part of a molten metal molding apparatus according to an embodiment of the present invention.

Fig. 4 is a simplified explanatory view showing a main part of a molten metal molding apparatus according to an embodiment of the present invention.

Fig. 5 is a main part sectional view showing a state where the reloaded metal material is completely pushed into the heating cylinder by the pushing portion (front end cylindrical portion) of the linear motion body in the molten metal molding apparatus according to the embodiment of the present invention.

Fig. 6 is a simplified explanatory view showing a main part of a molten metal molding apparatus according to an embodiment of the present invention.

Fig. 7 is a simplified explanatory view showing a main part of a conventional molten metal molding apparatus. In the figure:

1-a first retention plate; 2-a second holding plate; 3-connecting the shaft; 4-direct acting body; 4 a-press-fitting portion (front end cylindrical portion); 5-an electric servo motor; 6-motor driver; 7-a system controller; 8-driving a small belt wheel; 9-a passive pulley; 10-ball screw mechanism; 11-a screw shaft; 12-a nut body; 13-a load cell; 14-heating a cylinder; 15-a nozzle section; 15 a-a first nozzle portion; 15 b-a second nozzle portion; 16-inert gas supply means; 17-gas piping; 18-a gas supply port; 19-gas piping; 20-a gas supply port; 21-fixing the mold; 22-a movable mold; 23-lumen; 24-a syringe; 25-molten metal injection port; 26-a hydraulic cylinder; 27-an injection push rod; 27 a-push rod joint; 30-a metallic material; 31-block member.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 to 6 are views of a molten metal molding apparatus according to an embodiment of the present invention (hereinafter, referred to as the present embodiment), and fig. 1 to 4 are simplified explanatory views of main portions of the molten metal molding apparatus according to the present embodiment.

In fig. 1 to 4, 1 is a first holding plate provided so as to be movable forward and backward on a not-shown rail member for a melting system unit, 2 is a second holding plate provided so as to be movable forward and backward and opposed to the first holding plate on a not-shown rail member for a melting system unit, 3 is a plurality of connecting shafts integrally connecting the first holding plate 1 and the second holding plate 2, 4 is provided so as to be movable forward and backward (or provided so as to be movable forward and backward by being inserted and guided by the connecting shafts 3) on a not-shown rail member for a melting system unit, and a linear body driven forward and backward as described later is provided between the first holding plate 1 and the second holding plate 2, 5 is an electric servo motor for pressing in a metal material mounted on the second holding plate 2, 6 is a motor driver for driving and controlling the electric servo motor 5, 7 is a system controller for overall control of a molten metal molding apparatus, the system controller 7 refers to measurement information and timing information from various sensors, not shown, and controls the operation of each part of the molten metal molding machine based on various programs prepared in advance. The system controller 7 refers to an output of an encoder, not shown, attached to the electric servomotor 5 with respect to the electric servomotor 5, and issues a drive command for velocity feedback control via the motor driver 6 so as to drive the linear motion body 4 by velocity feedback control along the position axis.

Reference numeral 8 denotes a driving small pulley fixed to the electric servomotor 5, 9 denotes a driven pulley which transmits rotation of the electric servomotor 5 through the driving small pulley 8 and a timing belt, not shown, 10 denotes a ball screw mechanism which includes a screw shaft 11 and a nut body 12 and converts the rotational motion into linear motion, 11 denotes a screw shaft which is rotatably held on a second holding plate and to whose end the driven pulley 9 is fixed, and 12 denotes a nut body which is screwed with the screw shaft 11 and moves linearly with the rotation of the screw shaft 11 and whose end is fixed to a load sensor 13 fixed to the linear body 4. The rotation of the electric servo motor 5 is transmitted to the screw shaft 11 through the driving small pulley 8, a timing belt, not shown, and the driven pulley 9, and is integrated with the nut body according to the rotation direction of the screw shaft 11, thereby driving the linear body 4 and the load sensor 13 forward or backward.

The linear motion body 4 is a member for pushing a cylindrical metal material 30 before melting, which will be described later, into the heating cylinder 14 from an opening at the rear end of the heating cylinder 14, and the linear motion body 4 is provided with a pushing portion 4a, which is a front-end cylindrical portion, having an outer diameter substantially equal to the inner diameter of the heating cylinder 14, which will be described later. Further, the outer periphery of the press-fitting portion 4a of the linear motion body 4 which can enter the heating cylinder 14 described later can slide with respect to the inner periphery of the heating cylinder 14, and in a state where the press-fitting portion 4a enters the heating cylinder 14, there can be substantially no gap between the inner periphery of the heating cylinder 14 and the outer periphery of the press-fitting portion 4a of the linear motion body 4, so that the rear end side of the heating cylinder 14 can be substantially sealed from the outside air by the press-fitting portion 4 a. In the present embodiment, as described later, the pushing portion 4a of the direct acting body 4 is controlled to be positioned in the heating cylinder 14 except when a new cylindrical metal material 30 is supplied into the heating cylinder 13. In the present embodiment, the metal material 30 before melting, which will be described later, can be completely pushed into the heating cylinder 14, which will be described later, by the pushing portion 4a of the linear motion member 4, regardless of the amount of the molten material to be supplied, as described later.

Reference numeral 14 denotes a heating cylinder whose tip end side is fixed to the first holding plate 1, and the heating cylinder 14 of the present embodiment is configured without a mold (oxide film peeling portion) on its rear end side, unlike the conventional heating cylinder described above. The inner circumference diameter of the heating cylinder 14 is set to have a predetermined amount of clearance between the inner circumference of the heating cylinder 14 and the outer circumference of the cylindrical metal material 30 described later, and is set to be substantially the same as the outer circumference diameter of the press-fitting portion 4 of the linear motion member 4. Reference numeral 15 denotes a nozzle portion provided integrally with the heating cylinder 14 on the front end side of the heating cylinder 14, and the nozzle portion 15 includes: a first nozzle portion 15a of a substantially "ヘ" shape provided on the front end side of the heating cylinder 14 and including an upward inclined tube portion and a downward inclined tube portion connected to the upward inclined tube portion; and a second nozzle portion 15b which is a vertical pipe and which houses the front end portion of the first nozzle portion 15a and drops and supplies the molten metal discharged from the heating cylinder 14 through the first nozzle portion 15a into an injection passage 24, which will be described later. Although not shown, the belt heater is wound around the outer peripheries of the heating cylinder 14 and the nozzle portion 15 in the same manner as in the configuration of fig. 7.

Reference numeral 16 denotes an inert gas supply device which supplies an inert gas pressurized (pressurized to a pressure sufficiently exceeding the atmospheric pressure) into the rear end side of the heating cylinder 14 and the nozzle portion 15, 17 denotes a gas pipe which supplies the inert gas from the inert gas supply device 16 into the rear end side of the heating cylinder 14 through a gas supply port 18 provided in the outer peripheral portion of the rear end side of the heating cylinder 14, and 19 denotes a gas pipe which supplies the inert gas from the inert gas supply device 16 into the nozzle portion 15 through a gas supply port 20 provided in the upper portion of the nozzle portion 15. The inert gas supply device 16 is controlled by the system controller 7 to continuously supply the pressurized inert gas into the rear end side of the heating cylinder 14 and the nozzle portion 15.

Although not shown, the fixed mold 21 is mounted on a fixed die plate, the movable mold 22 is mounted on a movable die plate that can move forward and backward, the movable mold 22 can be clamped (closed) and opened by moving forward and backward of the movable die plate, and the cavity 23 can be formed by the fixed mold 21 and the movable mold 22 in a state where clamping is completed.

Reference numeral 24 denotes an injection cylinder whose end is fixed to the fixed mold 21, 25 denotes a molten metal injection port formed in an upper portion of an outer periphery of the injection cylinder 24 so as to face a front end opening (lower opening) of the second nozzle unit 15b of the nozzle unit 15, 26 denotes a hydraulic cylinder for injecting and filling molten metal, and 27 denotes an injection plunger capable of moving forward and backward in the injection cylinder 24, and here, for the sake of simplicity of illustration, the injection plunger 27 is shown as a member integrated with a piston rod of the hydraulic cylinder 26, but actually, a rod portion of the injection plunger 27 having a plunger joint 27a is connected and fixed to a front end of the piston rod of the hydraulic cylinder 26. The hydraulic cylinder 26 is controlled by the system controller 7 via a control valve or a valve controller, not shown, to advance or retract the injection rod 27.

Reference numeral 30 denotes a metal material, and in each drawing, a columnar metal material before melting, a semi-molten metal material, or a molten metal material is collectively denoted by reference numeral 30. In each figure, the metallic material 30 shown most densely, the metallic material 30 shown in a mesh form, and the metallic material 30 shown in dotted lines respectively show a molten state, a semi-molten state, and a solidified state.

Next, the operation of the molten metal molding apparatus according to the present embodiment will be described with reference to fig. 1 to 4. In the present embodiment, the system controller 7 performs control so that the press-fitting portion 4a of the linear motion body 4 is positioned in the heating cylinder 14 except when a new cylindrical metal material 30 is supplied. When the time point before the new cylindrical metal material 30 is press-fed into the heating cylinder 14 is reached, the linear motion body 4 is driven to retreat, and the linear motion body 4 is positioned at the retreat limit position. In synchronization with the backward movement of the linear motion body 4, the preheated cylindrical metal material 30 is rapidly taken out and conveyed by a not-shown material supply robot from a not-shown preheating device that holds the interior thereof with an inert gas medium in accordance with a command from the system controller 7, and the cylindrical metal material 30 gripped by the material supply robot is positioned so as to face the opening at the rear end of the heating cylinder 14. At this time, as shown in fig. 1, the metallic material 30 first pushed into the heating cylinder 14 by the pushing portion 4a of the linear actuator 4 is filled by a predetermined amount from the upward inclined tubular portion of the first nozzle portion 15a having a substantially ヘ shape to a halfway position in the heating cylinder 14 (a position closer to the rear end in the heating cylinder 14) in the portion of the inside of the heating cylinder 14 and the metallic material 30 is gradually melted as it moves from the position closer to the rear end in the heating cylinder 14 to the nozzle portion 15, and the metallic material 30 is completely melted in the nozzle 15 (the upward inclined tubular portion of the first nozzle portion 15 a). Also, at this time, the injection plunger 27 is located at the retreat restricting position. As described above, the pressurized inert gas is supplied from the inert gas supply device 16 into the rear end side of the heating cylinder 14, the rear end side of the heating cylinder 14 is filled with the inert gas, the pressurized inert gas is supplied from the inert gas supply device 16 to the second nozzle portion 15b of the nozzle portion 15, and the nozzle portion 15 is filled with the inert gas.

As described above, when the cylindrical metal material 30 gripped by the unillustrated material supply robot is positioned so as to face the opening at the rear end of the heating cylinder 14, immediately in response to a command from the system controller 7, the material supply robot relieves the gripping force of the cylindrical metal material 30 to allow the metal material 30 to be pushed in (needless to say, the positioning accuracy of the metal material 30 is maintained at this time), and in response to a command from the system controller 7, the electric servo motor 5 is rotated in a predetermined direction by the motor driver 6 to advance the linear motion body 4, and as shown in fig. 2, the cylindrical metal material 30 is pushed into the heating cylinder 14 from the opening at the rear end of the heating cylinder 14 by the pushing section 4a of the linear motion body 4. This press-fitting is performed quickly so that the columnar metal material 30 is completely press-fitted into the heating cylinder 14 regardless of the amount of the molten material supplied at one time. In short, the metal material refilled only in accordance with the stroke of supplying the amount of the molten material (the amount of the metal material filled into the mold) is not pushed in as in patent document 1 and the like, but in the present embodiment, the refilled metal material is pushed completely into the heating cylinder 14 filled with the inert gas regardless of the amount of the molten material supplied. Therefore, in the conventional technique such as patent document 1, when the amount of molten material supplied is small, the metal material to be refilled cannot be completely pushed into the heating cylinder, and a part of the metal material is exposed to air for a long time to be oxidized seriously, or a part of the metal material is exposed to air for a long time to be lowered in temperature, which is never caused in the present embodiment. Further, in the present embodiment, since the heating cylinder 14 is configured without a die (oxide film peeling portion) on the rear end side thereof and a predetermined amount of clearance is provided between the inner periphery of the heating cylinder 14 and the outer periphery of the cylindrical metal material 30, when the cylindrical metal material 30 is pressed into the heating cylinder 14, a large resistance is not generated when entering the heating cylinder as in the prior art, so that the cylindrical metal material 30 can be smoothly and quickly pressed into the heating cylinder 14, the pressing speed can be increased, the oxidation of the metal material 30 can be prevented, and the pressing speed can be increased, thereby shortening the casting cycle.

In addition, when the reloaded metal material 30 is completely pushed into the heating cylinder 14, the pushing portion 4a of the linear motion member 4 is in a state of substantially sealing the rear end side of the heating cylinder 14 from the outside air, and oxidation of the metal material 30 in the heating cylinder 14 can be suppressed as much as possible. Further, although there is substantially no gap between the inner periphery of the heating cylinder 14 and the outer periphery of the press-fitting portion 4a of the linear motion body 4, it is difficult to say that the inner periphery of the heating cylinder 14 and the outer periphery of the press-fitting portion 4a of the linear motion body 4 are configured such that they slide in accordance with the relationship between the linear bearing and the member guided by the linear bearing to perform the linear motion, and therefore, the air is not introduced into the rear end of the heating cylinder 14 at all times, because the pressurized inert gas is supplied into the rear end of the heating cylinder 14 at all times, even if the inert gas leaks from the space between the inner periphery of the heating cylinder 14 and the outer periphery of the press-fitting portion 4a of the linear motion body to the outside little. Accordingly, in a state where the pushing portion 4a of the linear motion body 4 enters the heating cylinder 14, the amount of the inert gas to be supplied into the rear end of the heating cylinder 14 is only required to be extremely small, and thus the inert gas can be saved.

Fig. 5 is a partial cross-sectional view showing a state where the reloaded metal material 30 is completely pushed into the heating cylinder 14 by the pushing section 4a of the linear motion body 4, and in this state, as shown in the drawing, the pushing section 4a of the linear motion body 4 enters the heating cylinder 14, and there is substantially no gap between the inner periphery of the heating cylinder 14 and the outer periphery of the pushing section 4a of the linear motion body.

When the linear motion body 4 is further forward driven in accordance with a command from the system controller 7 after the reloaded metallic material 30 is completely pushed into the heating cylinder 14, the reloaded metallic material 30 pressed by the pushing section 4a of the linear motion body 4 comes into contact with the previous metallic material 30, and then, when the linear motion body 4 is further forward driven, the reloaded metallic material 30 sequentially pushes the previous metallic material 30 forward, and by this pushing, the metallic material 30 (the melted metallic material (molten metallic solution) 30) discharged from the nozzle section 15 is rapidly dropped and supplied (that is, the molten solution is supplied) into the injection cylinder 24 from the molten metal inlet 25 of the injection cylinder 24 as shown in fig. 3.

Of course, the amount of the molten metal 30 supplied into the syringe 24 is determined by the forward stroke of the linear motion body 4 after the reloaded metal material 30 comes into contact with the previous metal material 30, but in the present embodiment, the reloaded metal material 30 is always completely pushed into the heating cylinder 14 by one pushing operation of the linear motion body 4, so that when the amount of the molten metal supplied at a time is less than the amount of one cylindrical metal material 30, for example, when the amount of the molten metal supplied is half that of one cylindrical metal material 30, a new metal material 30 is pushed into the heating cylinder 14 every two supply operations. In this case, the pushing portion 4a of the linear motion body 4 is stopped in the heating cylinder 14 from the end of the first molten solution supplying operation of the two molten solution supplying operations to the start of the next molten solution supplying operation. On the other hand, when the amount of the molten metal supplied at a time exceeds the amount of one cylindrical metal material 30, for example, when the amount of the molten metal supplied is 2 times the amount of one cylindrical metal material 30, two new metal materials 30 are continuously pushed into the heating cylinder 14 every time the operation of supplying the molten metal is performed. In the molten metal forming apparatus of the present embodiment, even when the amount of molten metal supplied at one time exceeds the amount of one cylindrical metal material 30, the amount can be easily handled, and thus a large product with increased weight can be easily cast.

As described above, when the molten metal 30 is supplied into the injection cylinder 24 by one shot amount, the forward driving of the linear motion body 4 is stopped. The above-described supply of the molten metal 30 into the injection cylinder 24 is performed at a high speed by driving the electric servo motor 5 by speed feedback control under a predetermined speed control condition to move the linear motion member 4 forward at a speed corresponding to the stroke (position). In this way, since the electric servo motor 5 is used as the drive source of the linear motion body 4 and the electric servo motor 5 is speed feedback-controlled in accordance with the stroke of the linear motion body 4, the forward position of the linear motion body 4 can be precisely controlled, and the amount of the molten metal 30 in one shot amount discharged from the nozzle section 15 can be stabilized.

Further, since the pressurized inert gas is continuously supplied into the nozzle portion 15 from the upper gas supply port 20, the nozzle portion 15 is filled with the inert gas, and the inert gas is also supplied into the barrel 24 from the distal end opening of the nozzle portion 15 through the molten metal injection port 25, the barrel 24 is also filled with the inert gas, and there is no possibility that the metal material is oxidized in the process of supplying the molten solution of the molten metal 30 into the barrel 24.

When the supply of the molten metal 30 of one shot amount into the injection cylinder 24 is completed, the hydraulic cylinder 26 is driven and controlled immediately in accordance with a command from the system controller 7, whereby the injection plunger 27 is first driven forward at a low speed to perform well-known evacuation, and then the injection plunger 27 is continuously driven forward at a high speed, whereby the molten metal 30 is rapidly injected and filled into the cavity 23 from the inside of the injection cylinder 24. Fig. 4 shows a state in which the molten metal 30 is completely filled into the cavity 23.

Since the injection and filling of the molten metal 30 into the cavity 23 is performed by the same molten metal molding (casting) as in the case of the cold chamber die casting machine, the injection and filling speed and the size of the molten metal passage area can be set to be optimal for each product as compared with the conventional technique shown in fig. 7. In the present embodiment, since a product in which the amount of the molten metal supplied at one time exceeds the amount of the one columnar metal material 30 can be cast, a larger and heavier product can be cast. Further, by adopting a cold chamber type control method which has been conventionally used, the behavior of injection and filling can be stabilized. In addition, in the cold chamber type molten metal forming (casting), since the block member (31 in fig. 4 indicates the block member) connected to the cast product is also taken out simultaneously with the cast product when the cast product is taken out from the mold, the molten metal 30 injected and filled into the mold per shot amount can be made into a fresh (less heat history) material which is not heated → cooled → heated, and can contribute to the improvement of the quality of the cast product.

Fig. 6 shows, as a reference, a case of casting in which the pressing stroke L1 of the linear motion body 4 for supplying the molten metal at a time is set to be longer than the entire length L2 of the one columnar metal material 30, and the amount of the molten metal supplied at a time is set to be larger than the amount of the molten metal supplied at the one columnar metal material 30.

As described above, the present embodiment combines: the advantage of a compact apparatus-integrated structure for melting the metal material 30 by the heating cylinder 14 can be achieved without using a melting furnace; and a cold chamber die casting machine which is excellent in versatility and can mold (cast) a product having an increased weight, wherein the heating cylinder 14 is structured so that the oxide film peeling section (die) is not provided on the rear end side thereof, and a predetermined amount of clearance is provided between the inner periphery of the heating cylinder 14 and the outer periphery of the columnar metal material 30, and the outer periphery of the press-fitting section 4a of the linear motion member 4 which can be inserted into the heating cylinder 14 can be slid with respect to the inner periphery of the heating cylinder 14, whereby the new columnar metal material 30 can be completely press-fitted into the heating cylinder 14 regardless of the amount of the metal material to be filled into the die. Accordingly, when the columnar metal material 30 is press-fitted into the heating cylinder 14, since a large resistance is not generated at the time of entering the heating cylinder as in the conventional art, the columnar metal material 30 can be smoothly press-fitted into the heating cylinder 14 at a high speed, the press-fitting speed can be increased, and even when the amount of the molten metal 30 to be filled into the mold is small, a trouble that a part of the metal material to be refilled is exposed to the air for a long period of time as in the conventional art does not occur, so that the oxidation of the new metal material 30 can be minimized, and the possibility of the temperature drop of the new metal material 30 can be eliminated. Furthermore, since there is substantially no gap between the inner periphery of the heating cylinder 14 and the outer periphery of the press-fitting portion 4a of the linear motion body 4, the rear end side of the heating cylinder 14 can be substantially sealed from the outside air by the press-fitting portion 4a of the linear motion body 4 by positioning the press-fitting portion 4a of the linear motion body 4 in the heating cylinder 14 except when a new cylindrical metal material 30 is supplied, and oxidation of the metal material 30 in the heating cylinder 14 can be suppressed as much as possible. In addition, since the pressurized inert gas is supplied into the rear side of the heating cylinder 14, the possibility of oxidation of the metal material 30 in the heating cylinder 14 can be eliminated. Further, since the press-fitting stroke of the linear motion body 4 for supplying the molten material can be set to be longer than the entire length of the one cylindrical metal material 30, it is possible to easily cast a large product having a large weight, in which the amount of the molten material 30 filled into the mold exceeds the amount of the one cylindrical metal material 30.

Claims (5)

1. A molten metal forming apparatus in which a preheated cylindrical metal material is supplied into a heating cylinder in order from the rear end side of the heating cylinder, the metal material is pressed into the front end side of the heating cylinder in order by a linear body, and the metal material is gradually melted as it moves from the rear end side to the front end side of the heating cylinder by heating with a heater attached to the heating cylinder,

a predetermined amount of clearance is provided between the inner circumference of the heating cylinder and the outer circumference of the cylindrical metal material, and the outer circumference of the front end cylindrical portion of the linear motion member which is press-fitted into the heating cylinder is slidable relative to the inner circumference of the heating cylinder,

the new cylindrical metal material can be completely pressed into the heating cylinder regardless of the amount of the metal material charged into the mold.

2. The molten metal forming apparatus according to claim 1,

the front end cylindrical portion of the linear motion body is positioned in the heating cylinder except when a new metal material having a cylindrical shape is supplied into the heating cylinder.

3. The molten metal forming apparatus according to claim 1,

the interior of the rear end side of the heating cylinder is kept in an inert gas atmosphere.

4. The molten metal forming apparatus according to claim 1,

the molten metal is supplied by dropping and supplying the molten metal into the injection cylinder from a nozzle portion provided at the distal end side of the heating cylinder, and the molten metal supplied into the injection cylinder is injected and filled into the mold by an injection plunger.

5. A molten metal forming apparatus according to claim 4,

the pressing stroke of the linear motion body for supplying the molten metal may be set to be longer than the entire length of one of the columnar metal materials.