JP6645903B2 - Uniaxial eccentric screw pump for transferring molten metal and die casting apparatus equipped therewith - Google Patents

Description

  The present invention relates to a die casting apparatus.

In a die casting apparatus, a casting is obtained by pressure-feeding a molten metal into a cavity formed by clamping a pair of molds.
Here, the cold-chamber die-casting apparatus is formed in a mold 71 that press-contacts a fixed mold 71a and a movable mold 71b to form a cavity 71c, as shown in the schematic diagram of FIG. A sleeve 172 that communicates with the cavity 71c through the runner 71m; a ladle 174 that supplies molten metal (molten metal) M from a filling port 172k at the rear of the sleeve to a pressurizing chamber 172p in the sleeve 172; And a plunger 173 for injecting the molten metal M supplied to the cavity 71c.

  In this type of die casting apparatus, a predetermined amount of molten metal M is pumped from a pot by a ladle 174 serving as a pouring device, and the molten metal M is supplied from a filling port 172k to a pressurizing chamber 172p by the ladle 174. The molten metal M supplied to the mold 71 is pressure-filled into the mold 71 by the plunger 173.

  In addition, as a pouring device using a device other than a ladle, for example, in Patent Document 1, a moving magnetic field is generated inside a cylindrical duct by an inductor in which a coil is wound around a magnetic yoke to apply thrust to the molten metal. An electromagnetic pump for molten metal is disclosed.

JP 2006-341281 A

  However, when supplying molten metal to the sleeve, in a pouring device using a ladle, the oxide is generated by the molten metal coming into contact with air while the molten metal is being drawn from the ladle and poured into the sleeve. Problem. If a hard part is present in the cast product due to the mixing of the oxide into the molten metal, it causes tool breakage during cutting. In addition, in a pouring device using a ladle, there is a problem that a lid cannot be formed in a furnace (pot), heat is released and a working environment becomes high temperature, and a problem that foreign matters and bubbles are mixed in molten metal occurs. is there.

  On the other hand, in a pouring device using an electromagnetic pump for molten metal, a moving magnetic field is generated inside a cylindrical duct by an inductor having a coil wound around a magnetic yoke to apply thrust to the molten metal. Therefore, even if the supply of the molten metal is stopped, there is a problem that the molten metal is excessively supplied by inertia due to the viscosity of the molten metal. That is, it is difficult for the molten metal electromagnetic pump to instantaneously stop the supply of the molten metal, and it is difficult to supply a high-precision quantitative supply.

  Accordingly, the present invention has been made in view of such a problem, and a single-shaft eccentric screw pump capable of pressure-feeding a molten metal in a closed circuit while securing the quantitativeness of molten metal supply, and a die casting including the same. It is an object to provide a casting device.

In order to solve the above problems, a single-axis eccentric screw pump for transferring molten metal according to one embodiment of the present invention includes a housing in which an axis is vertically arranged, and a plurality of bearings vertically arranged in the housing. An outer rotor rotatably supported and having a female screw-shaped inner surface; and an inner rotor having a male screw-shaped helical portion inserted into the outer rotor and having a base end connected to a drive shaft of a motor. A molten metal transferring uniaxial eccentric screw pump for transferring molten metal sucked from a suction port to a discharge port by performing eccentric movement while rotating the inner rotor with respect to a core, wherein the suction port is provided in the housing. Of the wetted part formed in the lower part of the molten metal pot and immersed in the molten metal in the molten metal pot, The inner rotor, the outer rotor, and a plurality of bearings supporting the outer rotor are formed of a ceramic material having heat resistance and thermal shock resistance, and among the liquid contact parts immersed in the molten metal, a liquid contact part without sliding is used. A certain housing is formed of a erosion resistant casting.

According to the uniaxial eccentric screw pump for transferring molten metal according to one embodiment of the present invention, among the wetted parts, the sliding portion that requires extremely high erosion resistance and abrasion resistance to molten metal has heat resistance and thermal shock resistance. And a liquid-contacting part that does not involve sliding is made of a relatively inexpensive erosion-resistant casting.
In other words, the inner rotor, the outer rotor, and a plurality of bearings that support the outer rotor are formed of a ceramic material as a liquid contact portion that is immersed in the molten metal, and the housing that is a liquid contact component that does not involve sliding is formed of a erosion resistant casting. Therefore, even if the liquid contact portion is exposed to a high-temperature molten metal exceeding 700 ° C., for example, the sealing performance of the sliding portion between the outer rotor and the inner rotor and the sealing performance of the shaft sealing portion of the inner rotor can be maintained. A uniaxial eccentric screw pump for transferring molten metal can be provided at a lower cost than when the liquid contact part is made of a ceramic material.

  According to the single-axis eccentric screw pump for transferring molten metal, the housing can be vertically arranged so that the suction port is immersed in the molten metal in the pot by the housing structure in which the axis is vertically arranged. By performing eccentric movement while the inner rotor rotates, the molten metal sucked from the lower suction port can be quantitatively transferred to the discharge port. Therefore, if a pouring pipe is connected from the discharge port to the sleeve of the die casting apparatus, the molten metal can be pressure-fed in a closed circuit while securing the quantitativeness of molten metal supply.

  Here, the single-axis eccentric screw pump for transferring molten metal according to one aspect of the present invention further includes an extension support structure for supporting the single-axis eccentric screw pump at a position extended from the upper motor to the pot side; A hollow frame-shaped intermediate frame made of erosion-resistant casting interposed between the frame on which the motor is mounted and the housing; and a base end of the inner rotor inserted through the intermediate frame. An inner shaft that connects a portion and a drive shaft of the motor, and a plurality of connection rods made of erosion-resistant casting that support the frame, the housing, and the intermediate frame by pressing each other in the axial direction, and the inner rotor It is preferable that the intermediate frame itself is rotatably supported at the lower end of the intermediate frame via the ceramic material bearing. With this configuration, the uniaxial eccentric screw pump can be supported at the position extended toward the pot by the extended support structure made of the erosion-resistant casting, which is more suitable as a uniaxial eccentric screw pump for transferring molten metal. .

  Further, in the single-shaft eccentric screw pump for transferring molten metal according to one aspect of the present invention, the plurality of bearings supporting the outer rotor and the bearing supporting an intermediate portion of the inner rotor are cylinders using an atmospheric fluid as a lubricating fluid. A plurality of bearings for supporting the outer rotor, each having a cylindrical outer peripheral surface having a tapered outer surface whose diameter is reduced downward from an intermediate portion in the axial direction to a lower end portion; The sliding bearing that supports the middle part of the lower housing has a tapered outer surface on the outer peripheral surface of the cylindrical shape, the diameter of which decreases upward from the middle part in the axial direction to the upper end, and the housing has a suction port. , An upper housing having an intermediate housing and a discharge port in this order from the lower side to the upper side, and the lower housing and the intermediate housing An inner peripheral surface radially opposed to the plurality of bearings supporting the outer rotor, a cylindrical inner surface slidingly contacting the outer peripheral surface and the tapered outer surface of each bearing, and a tapered inner surface expanding upward in diameter; The frame has a cylindrical inner surface slidingly contacting the outer peripheral surface and the tapered outer surface of the slide bearing on an inner peripheral surface radially opposed to a slide bearing supporting an intermediate portion of the inner rotor, and a tapered inner surface reduced in diameter upward. It is preferred to have

  With such a configuration, even when a gap is formed due to a difference in thermal expansion between the fitting parts of the liquid contact parts, each tapered outer surface of each ceramic material bearing is made resistant to erosion by the discharge pressure applied in the housing. By being pressed against the inner surface of each taper of the cast housing, automatic alignment of the rotation axes of the outer rotor and the inner rotor becomes possible. Therefore, it is more suitable as a uniaxial eccentric screw pump for transferring molten metal.

Furthermore, in order to solve the above problems, a die casting apparatus according to one embodiment of the present invention is configured such that a suction chamber is immersed in a molten metal in a pot in which a cold chamber type casting apparatus body and a molten metal are stored. A vertically disposed uniaxial eccentric screw pump, a pouring pipe interconnecting a sleeve of the casting apparatus main body and a discharge port of the uniaxial eccentric screw pump, and any one of the present invention as the uniaxial eccentric screw pump. And a uniaxial eccentric screw pump for transferring molten metal according to the above aspect.

According to the die casting apparatus according to one aspect of the present invention, as the uniaxial eccentric screw pump, have either uniaxial eccentric screw pump for molten metal transport according to one aspect of the present invention, the uniaxial eccentric screw pump inlet Is placed vertically so as to be immersed in the molten metal in the pot, and the pouring tube connects the sleeve of the cold chamber type casting device body and the discharge port of the uniaxial eccentric screw pump to each other, so that the molten metal in the pot is cast. A fixed amount can be supplied to the sleeve of the apparatus main body via the pouring pipe . This makes it possible to configure a closed circuit in which the molten metal does not come into contact with air even though the cold chamber type die casting apparatus is used.

  Therefore, according to the die casting apparatus according to one embodiment of the present invention, there is a problem that a furnace cannot be covered, a problem that heat is released and a working environment becomes high temperature, which is caused by a method of supplying molten metal by a ladle, It is possible to avoid problems such as mixing of air bubbles. In addition, when the molten metal generated by the method of supplying molten metal using a ladle or the method of supplying molten metal by an electromagnetic pump for molten metal comes into contact with air, oxides are generated. In addition, the problem that a hard part is present in the steel and causes breakage of the tool during cutting can be avoided.

  Here, in the die casting apparatus according to one aspect of the present invention, the uniaxial eccentric screw pump includes a servomotor that rotationally drives the inner rotor, and a control unit that controls the servomotor, and the control unit includes: It is preferable to control the supply amount of the molten metal by the uniaxial eccentric screw pump based on the supply amount of the molten metal by the plunger of the casting device main body.

  With such a configuration, a single-axis eccentric screw pump is driven based on the supply amount of the molten metal by the plunger of the casting apparatus main body by using a servomotor as a driving method of the single-axis eccentric screw pump. By controlling the supply amount of the molten metal by the above, the supply amount of the molten metal from the uniaxial eccentric screw pump can be made to accurately follow the filling amount on the casting apparatus main body side. Therefore, it is more suitable for constructing a closed-circuit die casting apparatus for injecting molten metal into the sleeve of the casting apparatus body with low pulsation.

  As described above, according to the present invention, molten metal can be pressure-fed in a closed circuit while securing the quantitativeness of molten metal supply.

It is an explanatory view showing one embodiment of a die-casting device concerning one mode of the present invention by a typical section. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one Embodiment of the uniaxial eccentric screw pump for molten metal transfer which concerns on one aspect of this invention, Comprising: The figure has shown the cross section along the axis. It is a figure explaining the structure of the slide bearing which supports the lower part of an outer rotor, The figure (a) is a front view, (b) is sectional drawing along an axis, (c) is a rear view. It is a figure explaining the structure of the slide bearing which supports the upper part of an outer rotor, FIG. 3A is a front view, FIG. 3B is a sectional view along an axis, and FIG. 3C is a rear view. It is a figure explaining the structure of the plain bearing which supports the middle part of an inner rotor, The figure (a) is a front view, (b) is sectional drawing which followed the axial line, (c) is a rear view. It is explanatory drawing of the pouring device using the ladle in the conventional cold chamber type die casting casting apparatus.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate. Here, the die casting apparatus of the present embodiment is a cold chamber type die casting machine capable of supplying hot water in a closed circuit, and is formed by press-fitting a molten metal such as an aluminum alloy into a predetermined mold and solidifying it. The product is cast.

  The drawings are schematic. Therefore, it should be noted that the relationship between the thickness and the planar dimension, the ratio, and the like are different from the actual ones, and the drawings include portions having different dimensional relationships and ratios. The embodiments described below exemplify an apparatus and a method for embodying the technical idea of the present invention, and the technical idea of the present invention is based on the material, shape, structure, and arrangement of the component parts. Are not specified in the following embodiments.

  As shown in FIG. 1, this die casting apparatus includes a uniaxial eccentric screw pump (hereinafter, also simply referred to as “screw pump”) 60 for transferring molten metal, a casting apparatus main body 70, and a pouring pipe 74 connecting these to each other. ing. The casting apparatus main body 70 has a mold 71 and a sleeve 72. The screw pump 60 is provided as a pouring device for the pot 80 in which the molten metal M is stored. The pouring pipe 74 is connected so that the molten metal M fed from the screw pump 60 at a constant pressure can be supplied to the sleeve 72 of the casting apparatus main body 70.

  The mold 71 is a metal mold for casting a molded product, and has a fixed mold 71a and a movable mold 71b that are opposed to each other. In the mold 71, the runner 71m and the cavity 71c are defined in the mold 71 by pressing the pair of fixed molds 71a and the movable molds 71b with each other.

The sleeve 72 is connected to a lower side surface of the mold 71. The sleeve 72 is a substantially cylindrical member whose both ends in the axial direction are open, and the internal space is a pressure chamber 72p. The pressurizing chamber 72p communicates with the cavity 71c via a runner 71m.
On a rear upper surface of the sleeve 72, a hot water supply port 72k for supplying the molten metal M to the pressurizing chamber 72p is provided. One end of the pouring pipe 74 is connected to the hot water supply port 72k, and the other end of the pouring pipe 74 is connected to the discharge port 5a of the screw pump 60. In the sleeve 72, the molten metal M fed from the screw pump 60 at a constant pressure is temporarily stored in the pressurizing chamber 72p.

  A plunger 73 is provided axially rearward of the sleeve 72. The plunger 73 is connected to an actuator (not shown) via a rod 73b on the rear side. The plunger 73 is slid in the axial direction within the sleeve 72 by driving the actuator, and can inject the molten metal M supplied from the screw pump 60 to the pressurizing chamber 72p into the cavity 71c.

Next, the screw pump 60 will be described in detail.
As shown in FIG. 1, the screw pump 60 includes a substantially cylindrical frame 21 having an axis vertically arranged above a pot 80, a servomotor 22 mounted on an upper surface of the frame 21, and a lower portion of the frame 21. And a pump body 30 to be mounted. The frame 21 is formed of, for example, SS400 (rolled steel material for general structure).
The control unit 90 is connected to the servomotor 22 via wiring capable of transmitting and receiving electric power and signals necessary for driving the servomotor 22. The control unit 90 includes a microcomputer and a driver for the servomotor 22. The control unit 90 executes the pouring amount control process, and based on the supply amount of the molten metal M by the plunger 73 of the casting device main body 70, the screw pump 60 is controlled so as to have the same amount as the filling amount on the casting device main body 70 side. To control the supply amount of the molten metal M.

  The pump body 30 is mounted on the lower surface of the frame 21 via the intermediate frame 7 for extended support so as to be immersed in the molten metal M in the pot 80. The intermediate frame 7 is a hollow cylindrical member formed of a erosion-resistant casting. The intermediate frame 7 has a flange formed on an upper part thereof, an axis of which is vertically fixed to a lower surface of the frame 21 by a plurality of bolts. In the intermediate frame 7, a long intermediate shaft 10 connected to the inner rotor 1 of the pump main body 30 so as to be able to transmit the driving force of the driving shaft 22m of the servomotor 22 is provided with its axis extending vertically. The intermediate shaft 10 is formed of an alloy tool steel material (SKD61).

  Around the pump body 30 and the intermediate frame 7, a plurality of long connecting rods 11 formed of a solid cylindrical erosion-resistant casting are arranged with their axes vertically separated in the circumferential direction. . Each connecting rod 11 has a large diameter head on the lower end side and a female screw on the upper end surface. Each connecting rod 11 is inserted from below into the insertion hole of the lower housing 9 such that the head at the lower part of the rod supports the pump body 30 from below.

  An annular flange 21f extending in the horizontal direction is formed at a lower portion of the frame 21. In each connection rod 11, the female screw at the top of the rod is fastened to the flange 21f by the rod fixing bolt 17. An annular disc spring washer 18 is interposed between the rod fixing bolt 17 and the flange 21f. The disc spring washer 18 is made of a nickel-based super heat-resistant alloy (for example, Inconel (registered trademark)), and in this example, a plurality of sheets are interposed in a stacked state.

  The frame 21 is supported by a support housing (not shown) above the pot 80 so that the pump body 30 is hung down into the pot 80. Thus, the pump body 30 is held at a height at which the pump body 30 is immersed in the molten metal M in the pot 80 in a state of being suspended from the frame 21. The other members of the screw pump 60 located above the pump body 30 are supported at a position higher than the upper surface of the molten metal M so as not to be immersed in the molten metal M in the pot 80.

As shown in an enlarged view in FIG. 2, the servomotor 22 has a surface 22 a on the drive shaft 22 m side mounted vertically on an upper surface of the frame 21. A cylindrical coupling shaft 20 is provided in the frame 21. The coupling shaft 20 is formed of, for example, SS400 (rolled steel material for general structure).
The coupling shaft 20 is rotatably supported on the inner peripheral surface of the frame 21 via the high-temperature environment bearing 19 via upper and lower ends of the outer peripheral surface. As the high-temperature environment bearing 19, for example, a rolling bearing (for example, a deep groove ball bearing) that can be applied in the atmosphere up to about 400 ° C. by using a high-temperature fluorine-based grease and molybdenum disulfide-based solid lubrication can be used.

  On the upper side of the coupling shaft 20, a mounting hole 20a for mounting the drive shaft 22m is provided. The drive shaft 22m is connected to an upper portion of the coupling shaft 20 by a fixed key 23 in a state where the drive shaft 22m is inserted into the mounting hole 20a. At the lower side of the coupling shaft 20, a mounting hole 20b for mounting the intermediate shaft 10 is provided coaxially with the mounting hole 20a. The upper end 10u of the intermediate shaft 10 is connected to a lower portion of the coupling shaft 20 by a fixed key 24 while being inserted into the mounting hole 20b.

The pump body 30 includes a housing 31 mounted on a lower portion of the intermediate frame 7, an outer rotor 2 having a female screw-shaped inner surface rotatably supported in the housing 31, and a male screw-shaped spiral portion 1 a inserted into the outer rotor 2. Inner rotor 1 provided. Both the inner rotor 1 and the outer rotor 2 are formed of silicon nitride.
The outer rotor 2 is disposed in the housing 31 via two cylindrical sliding bearings 3 and 4. Each of the two plain bearings 3 and 4 is formed of silicon nitride. The inner rotor 1 is rotatably supported at the lower end of the intermediate frame 7 through a cylindrical sliding bearing 6 made of silicon nitride.

Here, in the present embodiment, “silicon nitride (Si ₃ N ₄ )” has a mechanical strength necessary to perform the function required for the liquid contact part even in a state of being in contact with the molten metal M. Is selected as a ceramic material having heat resistance and thermal shock resistance capable of maintaining the above. For example, engineering ceramics (fine ceramics) having structural stability as heat resistance of 800 ° C. or higher, and having a thermal shock resistance of 500 ° C. or higher (dropping in water) and satisfying a predetermined strength reduction rate. .

  In addition, as a method for evaluating the thermal shock resistance, for example, the residual bending strength of a heated bending test piece (according to JIS R1601) after being subjected to thermal shock damage by dropping in water (JIS R1648 relative method) is measured, The strength reduction rate of the three-point bending strength with respect to the initial strength when no impact damage is given is calculated and determined. When the strength reduction rate satisfies the predetermined condition, the strength reduction rate is within 20%, preferably within 10%, more preferably within 5%.

  On the inner peripheral surface of the outer rotor 2, a spiral portion 2e having a female screw-shaped oval cross section is formed. The spiral portion 1a of the inner rotor 1 is housed in a female screw-shaped spiral portion 2e of the outer rotor 2. The female screw-shaped helical portion 2e formed inside the outer rotor 2 has a female screw-shaped pitch twice that of the spiral portion 1a of the inner rotor 1. The rotation axis of the inner rotor 1 is eccentrically arranged by a predetermined distance with respect to the rotation axis of the outer rotor 2. Thus, the molten metal can be quantitatively fed from the suction port 9a of the housing 31 to the discharge port 5a by performing eccentric motion with respect to the axis of the outer rotor 2 while the inner rotor 1 rotates.

  More specifically, the inner rotor 1 of the present embodiment has a male screw-shaped spiral portion 1a on the distal end side, a linear intermediate portion 1b, and a tapered base end portion 1c. The spiral portion 1a of the inner rotor 1 has a circular cross section eccentric with respect to its own rotation axis. The base end 1c of the inner rotor 1 is directly connected to the drive shaft 22m of the servomotor 22 via the intermediate shaft 10 arranged in the intermediate frame 7.

  In the present embodiment, the base end portion 1c of the inner rotor 1 and the front end portion 10s of the intermediate shaft 10 are connected by a cylindrical connection piece 8 that surrounds each other (hereinafter, also referred to as a “taper connection structure”). The connection piece 8 is formed from a erosion resistant casting. In the tapered connection structure of the present embodiment, a tapered outer surface 1m whose diameter is increased upward is provided on the outer peripheral surface of a portion surrounded by the connecting piece 8 at the base end 1c of the inner rotor 1. On the other hand, the connecting piece 8 is provided with a tapered inner surface 8m that increases in diameter upward on an inner peripheral surface that radially opposes the tapered outer surface 1m of the inner rotor 1.

  The tapered outer surface 1m and the tapered inner surface 8m are connected to each other by a fixed key 25 made of silicon nitride which is arranged so as to transmit a rotational force. A spring member 16 that urges both end surfaces in the direction away from each other is interposed between both end surfaces where the base end portion 1c of the inner rotor 1 and the front end portion 10s of the intermediate shaft 10 face each other. The spring member 16 is a cylindrical coil spring formed of silicon nitride.

  The intermediate shaft 10 has a flange 10t formed in an annular shape and having substantially the same diameter as the outer shape of the connecting piece 8 at an intermediate portion of the distal end 10s. The intermediate shaft 10 and the connection piece 8 are in a state where the upper end surface of the connection piece 8 is in axial contact with the flange 10t, and are fastened to each other by bolts (not shown).

  The intermediate portion 1b of the inner rotor 1 is rotatably supported via a slide bearing 6 on an inner peripheral surface of a lower end portion of the intermediate frame 7. The slide bearing 6 supporting the intermediate portion 1b is fixed to the intermediate frame 7 by a fixed key 15 made of silicon nitride. A plurality of annular labyrinth grooves 63 are formed in the axial direction between the upper end 1d of the intermediate portion 1b and the sliding bearing 6 (between opposing surfaces in the direction perpendicular to the axis) to form a seal structure. Have been.

  The housing 31 has a lower housing 9, an intermediate housing 13, and an upper housing 5 in order from the lower suction port 9a side to the upper discharge port 5a side in FIG. The lower housing 9, the intermediate housing 13, and the upper housing 5 are all formed of a erosion resistant casting.

  The lower housing 9 has a flat cylindrical shape with a larger diameter than the flange 21 f of the frame 21. In the lower housing 9, a molten metal suction port 9a is formed so as to penetrate the center along the axial direction. In the lower housing 9, a mounting hole 9 h for mounting the plurality of connection rods 11 made of the erosion-resistant casting is formed in a thick portion around the suction port 9 a so as to penetrate the mounting position of each connection rod 11. Is formed.

  The upper housing 5 has a hollow cylindrical shape having an outer diameter that fits in an inner region of the plurality of connecting rods 11 surrounding the upper housing 5. On the side wall surface of the upper housing 5, a discharge port 5a for molten metal is opened. The axis of the discharge port 5a faces in the horizontal direction, and the shape of the discharge port 5a is tapered so that the diameter increases from the inside to the outside.

  The intermediate housing 13 has a hollow cylindrical shape having an outer diameter substantially the same as that of the upper housing 5. In the side wall surface of the intermediate housing 13, an inlet 13h for guiding the molten metal M is formed substantially at the center in the axial direction. The axis of the inlet 13h is oriented in the horizontal direction, and when the pump body 30 is immersed in the melt M in the pot 80, the melt M flows from the inlet 13h through the outer peripheral surface of the outer rotor 2 and the inner peripheral surface of the intermediate housing 13. Introduced into the space between. As a result, the molten metal M spreads over the lubricating grooves 41 formed in the upper and lower sliding bearings 3 and 4 that support the outer rotor 2, and a lubricating structure using the molten metal M, which is an ambient fluid, as a lubricating fluid is constructed.

  The housing 31 has an inlay fitting portion in which the concave step portion and the convex step portion are fitted on the axially opposing surfaces of the lower housing 9, the intermediate housing 13, the upper housing 5, and the intermediate frame 7. ing. The lower, middle and upper housings 9, 13 and 5 are integrated with the lower end of the intermediate frame 7 by axially pressing the lower housing 9 and the flange 21f constituting the lower housing 9 and the flange 21f by the plurality of connecting rods 11. It is fixed to.

  The upper and lower ends of the outer rotor 2 are rotatably supported by a housing 31 via cylindrical slide bearings 3 and 4. The inner peripheral surfaces of the upper and lower sliding bearings 3 and 4 are externally fitted to sliding surfaces 2 c formed at both outer peripheral ends of the outer rotor 2. Thus, the sliding surfaces 2c at both ends of the cylindrical portion of the outer rotor 2 are rotatably supported in the housing 31 via the slide bearings 3 and 4.

  Further, the movement of the outer rotor 2 in the axial direction is also restricted by the upper and lower slide bearings 3 and 4. That is, the outer rotor 2 is formed in the center with a convex portion 2m that forms a contact surface in the axial direction with the upper and lower slide bearings 3 and 4 in an annular shape. The upper and lower sliding bearings 3 and 4 are arranged so as to sandwich the convex portion 2m from both sides in the axial direction.

  In the present embodiment, the slide bearing 4 that supports the upper portion of the outer rotor 2 is fixed to the upper inner peripheral surface of the intermediate housing 13 by a fixed key 14 made of silicon nitride. The sliding bearing 3 that supports the lower portion of the outer rotor 2 is fixed to the upper inner peripheral surface of the lower housing 9 by a fixed key 12 made of silicon nitride. A plurality of annular labyrinth grooves 53 are formed in the axial direction between the upper end 2d of the outer rotor 2 and the slide bearing 4 supporting the upper part thereof (between opposing surfaces in the direction perpendicular to the axis). A seal structure is formed.

  Here, each of the three slide bearings 3, 4, and 6 is a bearing (for example, an underwater bearing) using molten metal M, which is an ambient fluid, as a lubricating fluid. A plurality of lubrication grooves 41, 51, 61 are formed on the inner peripheral surface of each of the bearings 3, 4, 6 along the axial direction while being spaced apart in the circumferential direction.

  In particular, in the screw pump 60 of the present embodiment, tapered outer surfaces 45, 55, and 65 are formed on the outer peripheral surfaces of the bearings 3, 4, and 6 that support the outer rotor 2 and the inner rotor 1, respectively. Are formed on the inner peripheral surfaces of the housing 31 and the intermediate housing 13 in which are fitted the tapered inner surfaces 9n, 13n, 7n having taper angles corresponding to the tapered outer surfaces 45, 55, 65, respectively. It has a self-aligning structure.

More specifically, among the two bearings 3 and 4 supporting the outer rotor 2, the lower sliding bearing 3 has three lubrication grooves 41 equally arranged in the circumferential direction, as shown in FIG. The slide bearing 3 has an annular boss portion 44 on the inner peripheral side of the lower end surface at the time of mounting.
Each lubrication groove 41 of the sliding bearing 3 has a longitudinal groove 41a formed along the axial direction, and a lateral groove 41b communicating with the longitudinal groove 41a and formed in the boss 44 along the radial direction. On the outer peripheral surface of the slide bearing 3, a key groove 42 in which the fixed key 12 is mounted is formed along the axial direction at a position aligned with the key groove on the lower housing 9 side.

  The tapered outer surface 45, whose diameter is reduced toward the lower side from the middle part in the axial direction to the lower end part, is in sliding contact with the outer peripheral surface, which is lower at the time of mounting, on the sliding bearing 3. Is formed. As shown in FIG. 2, a concave step portion having a cylindrical inner surface and a tapered inner surface 9 n slidingly contacting the outer peripheral surface of the bearing 3 is formed above the inner peripheral surface of the lower housing 9. The lower slide bearing 3 is fitted into the recessed step portion and fixed by a fixed key 12.

  Of the two bearings 3 and 4 supporting the outer rotor 2, the upper sliding bearing 4 has three lubrication grooves 51 equally arranged in the circumferential direction, as shown in FIG. The sliding bearing 4 has an annular boss portion 54 on the inner peripheral side of the lower end surface at the time of mounting. Each lubrication groove 51 has a vertical groove 51a formed along the axial direction, and a horizontal groove 51b formed in the boss portion 54 along the radial direction in communication with the vertical groove 51a. A key groove 52 in which the fixed key 14 is mounted is formed along the axial direction on the outer peripheral surface of the slide bearing 4 at a position aligned with the key groove on the intermediate housing 13 side.

In addition to the three lubrication grooves 51 formed along the axial direction, the sliding bearing 4 has a plurality of stages (three stages in this example) along the circumferential direction on the inner peripheral surface which is upper at the time of mounting. An annular labyrinth groove 53 is formed in the axial direction so as to be separated. The three lubrication grooves 51 are formed only before the labyrinth groove 53.
Further, the sliding bearing 4 is formed with a tapered outer surface 55 whose diameter is reduced downward from an intermediate portion in the axial direction to a lower end portion on an outer peripheral surface which is a lower side at the time of mounting. As shown in FIG. 2, a concave step portion having a cylindrical inner surface and a tapered inner surface 13 n slidingly contacting the outer peripheral surface of the bearing 4 is formed above the inner peripheral surface of the intermediate housing 13. The upper slide bearing 4 is fitted into the concave step portion and fixed by a fixed key 14.

As shown in FIG. 5, the sliding bearing 6 supporting the intermediate portion 1b, which is an intermediate portion of the inner rotor 1, has three lubricating grooves 61 equally arranged in the circumferential direction. An annular boss portion 64 is formed on the slide bearing 6 on the inner peripheral side of a side end surface that is a lower side when mounted. Each lubrication groove 61 has a vertical groove 61a formed along the axial direction, and a lateral groove 61b formed in the boss portion 64 along the radial direction so as to communicate with the vertical groove 61a.
In addition to the three lubricating grooves 61, the sliding bearing 6 has a plurality of (in this example, three) circumferentially spaced circles formed on the inner peripheral surface, which is the upper side at the time of mounting, along the circumferential direction. It has an annular labyrinth groove 63. The three lubrication grooves 61 are formed only before the labyrinth groove 63.

  Further, on the outer peripheral surface of the sliding bearing 6, a tapered outer surface 65 is formed on the outer peripheral surface which is upper at the time of mounting, from the middle part in the axial direction to the upper end portion, and the diameter thereof is reduced toward the upper side. A key groove 62 for mounting the fixed key 15 of the slide bearing 6 is formed on the outer peripheral surface of the slide bearing 6 at a position aligned with the key groove on the intermediate frame 7 side along the axial direction. As shown in FIG. 2, a concave step having a cylindrical inner surface and a tapered inner surface 7n that slides on the outer peripheral surface of the bearing 6 is formed on the inner peripheral surface of the lower end of the intermediate frame 7, and the tapered inner surface 7n The sliding bearing 6 is fitted into the concave step portion having

  Here, the erosion-resistant casting employed in the present embodiment includes a base metal layer and an oxide layer formed as a coating layer on the surface of the base metal layer. The base metal layer has a ferrite region whose crystal structure is a ferrite structure on the surface layer side, and a pearlite region whose crystal structure is a pearlite structure below (inside) the ferrite region. In particular, in this erosion-resistant casting, the oxide layer includes a plurality of regions having different compositions from each other, and has a smaller amount of double carbides in the most surface region than in the region of the base metal layer. This erosion-resistant casting is much more excellent in erosion resistance than a conventional casting. Therefore, it can be suitably used as a metal melt contact member that comes into contact with a metal melt of aluminum or magnesium.

  Specifically, the base metal layer includes a carbon element and two or more base metal elements. The base metal layer according to the present embodiment is made of an alloy obtained by adding tungsten and cobalt based on SKD61 which is a general alloy tool steel as a material for a hot die. Specifically, in the present embodiment, the composition (% by weight) of the base metal layer is C 0.40 to 0.70%, Si 0.35 to 0.50%, Mn 0.50 to 0.70%, P <0.03%, S <0.02%, Cr 4.50 to 6.00%, Mo 0.50 to 0.75%, Co 0.70 to 0.90%, V 0.15 to 0.30 %, W 0.50 to 0.70%, Nb <0.10%, Al <0.10%, and the balance consists of Fe and inevitable impurity elements.

  The oxide layer is made of a thermal oxide of the base metal element. In the oxide layer on the base metal layer side, a reaction product of the carbon element in the base metal layer and two or more base metal elements is formed. Double carbide which is a material. In this erosion-resistant casting, a part of the oxide layer extends ciliately to the crystal grain boundary of the base metal layer to form a ciliated oxide. Since the ciliated oxide extends to the ferrite crystal grain boundaries, the oxide layer that exhibits an anchor effect and has excellent erosion resistance is firmly bonded to the base metal layer, and peeling is suppressed. Therefore, the erosion resistance is remarkably improved, and the deterioration of such characteristics is suppressed.

The erosion-resistant casting in the present embodiment can be manufactured as follows.
First, a base metal having the above composition is cast into a predetermined shape to obtain a metal member, and then an oxide layer is formed. In the step of forming the oxide layer, the metal member composed of the base metal is heated and maintained at a predetermined temperature in a furnace in a normal atmosphere, and gradually cooled in the furnace while controlling the temperature decreasing rate.
For example, the temperature of the metal member is raised to 780 to 980 ° C. over 2 hours, and is maintained at the temperature for a predetermined time. The temperature range maintained after the temperature rise is 780 to 980 ° C., and more preferably 900 ± 30 ° C. The holding time is adjusted according to the thickness of the metal member made of the base metal. For example, the holding time can be defined as one hour for a member thickness of 25 mm. By this heating / holding step, an oxide layer is formed and grown on the surface layer of the base metal layer, and a decarburized layer (ferrite trim) is formed. The released carbon element reacts with the constituent elements of the base metal layer. To form double carbides.

  Next, the temperature of the base metal is lowered at a predetermined cooling rate, and the cooling rate is maintained within a range of 30 ± 10 ° C./hour. The crystal structure changes from pearlite to ferrite on the surface layer side of the base metal layer by this cooling step. Then, the oxide that continues to grow from the previous step extends ciliately to the ferrite crystal grain boundaries. Through these steps, an oxide layer having excellent erosion resistance is formed on the surface of the base metal layer.

  It should be noted that it is extremely difficult to describe the characteristics of the “thermal oxide” generated by heating the base metal layer as specific structural characteristics for the erosion-resistant casting employed in the present embodiment. . “Thermal oxide” has a different morphological characteristic from an oxide obtained by a method of depositing a film material such as a CVD method, but it is difficult to specify the characteristic as a requirement. In other words, analyzing such features actually requires enormous costs and time. For example, although an optical microscope can be considered as a measuring method, in actuality, an oxide according to the present embodiment and an oxide according to the CVD method are manufactured, and the morphological characteristics are measured. This has to be found as an indicator, making this work impractical.

  However, the erosion-resistant casting employed in the present embodiment is characterized in that the oxide obtained by direct oxidation is characterized in that it is a “thermal oxide” and that “a part of the oxide layer is a base metal layer. And ciliary growth at the crystal grain boundaries of the matrix metal ", and" in the oxide layer on the base metal layer side, the reaction formation between the carbon element in the base metal layer and two or more base metal elements And a complex carbide. " The term refers to an oxide obtained by directly oxidizing the base metal layer by heating the base metal layer without supplying a reaction gas, and does not include an oxide obtained by a CVD method or the like. It is clear. Therefore, the structure of the erosion-resistant casting employed in the present embodiment is clearly specified.

Next, the operation of the die casting apparatus having the screw pump 60 and the functions and effects thereof will be described.
In this die casting apparatus, when the fixed mold 71a and the movable mold 71b are pressed against each other to form a cavity 71c and a runner 71m, and when the plunger 73 is located on the retreat side with respect to the hot water supply port 72k, the screw pump 60 performs pouring. Driven as a device.

  Here, the screw pump 60 of the present embodiment employs a uniaxial eccentric screw pump as the pump main body 30. The pump main body 30 rotatably supports the outer rotor 2 and the inner rotor 1 connected to the drive shaft 22m. The rotation axis is eccentrically arranged from the rotation axis of the outer rotor 2 by a predetermined distance, and the outer rotor 2 rotates dependently on the rotation of the inner rotor 1. Therefore, a universal joint (universal joint) is not required in the drive shaft coupling structure.

  The screw pump 60 is vertically arranged so that the suction port 9a is immersed in the molten metal M in the pot 80 by a housing structure in which the axis of the housing 31 of the pump body 30 is vertically arranged. On the other hand, since the inner rotor 1 performs an eccentric motion while rotating, the molten metal sucked from the lower suction port 9a can be quantitatively pumped to the discharge port 5a, so that the molten metal can be pressure-fed in a closed circuit while securing quantitativeness. It is.

  That is, when the inner rotor 1 is rotated by the drive shaft 22m of the servo motor 22, the inner rotor 1 rotates about its rotation axis, and the outer rotor 2 also rotates about its rotation axis with the movement of the spiral portion 1a of the inner rotor 1. The molten metal can be sent from the suction port 9a to the discharge port 5a under a constant pressure by the driven rotation in synchronization with the rotation of the first rotation.

  In particular, the screw pump 60 includes a servomotor 22 that rotationally drives the inner rotor 1 of the pump body 30 and a control unit 90 that controls the servomotor 22. Since the supply amount of the molten metal M by the screw pump 60 is controlled based on the supply amount of the metal M, the supply amount of the molten metal from the screw pump 60 to the supply amount of the molten metal of the plunger 73 on the casting apparatus main body 70 side. The supply amount of M can be made to follow with high accuracy.

  And since this die-casting casting apparatus is equipped with the pouring pipe 74 which connects the sleeve 72 of the casting apparatus main body 70 and the discharge port 5a of the pump main body 30 mutually, by this, the closed circuit which does not contact with air is provided. While being constructed, the molten metal M can be supplied quantitatively from the hot water supply port 72k of the sleeve 72 to the pressurizing chamber 72p via the pouring pipe 74.

  Next, by driving the plunger 73, the molten metal M supplied in a fixed amount to the pressurizing chamber 72p is filled into the cavity 71c via the runner 71m. The molten metal M filled in the cavity 71c is solidified in the cavity 71c to form a molded product.

As described above, according to the die casting apparatus of the present embodiment, the uniaxial eccentric screw pump 60 for transferring molten metal is used as a pouring apparatus for the sleeve 72 of the casting apparatus main body 70, and the pulsation is reduced by the screw pump 60. Because a closed circuit has been constructed that allows pouring in the furnace, there is a problem that the work environment becomes hot due to the escape of heat without the lid of the furnace, as occurs in the method of supplying molten metal by ladle. In addition, it is possible to avoid the problem that foreign matter and bubbles are mixed.
In addition, oxides may be generated when the molten metal comes into contact with air, such as those generated by the method of supplying molten metal by a ladder or the method of supplying molten metal by an electromagnetic pump for molten metal, Problems such as the inclusion of a hard part in the casting and the occurrence of tool breakage during cutting can also be avoided.

  In particular, according to the screw pump 60 provided in the die casting apparatus of the present embodiment, among the liquid contact parts immersed in the molten metal, at least the liquid contact parts with sliding have extremely high erosion resistance to the molten metal M, Since it is made of silicon nitride having excellent thermal shock resistance and wear resistance, it is excellent as a uniaxial eccentric screw pump for pouring equipment.

  That is, in the present embodiment, among the liquid contacting parts, the inner rotor 1, the outer rotor 2, the upper and lower sliding bearings 3 and 4 supporting the outer rotor 2, and the sliding bearing 6 supporting the inner rotor 1 are all formed of silicon nitride. Therefore, even if these liquid contact parts are exposed to a molten metal at a temperature of 700 ° C. or more, for example, the sealing performance of the sliding part between the outer rotor 2 and the inner rotor 1 and the sealing performance of the shaft sealing part of the inner rotor 1 can be maintained. it can.

  Furthermore, according to the screw pump 60 provided in the die casting apparatus of the present embodiment, the wetted parts of the wetted part immersed in the molten metal, such as the housing, which are not slidable, are formed of the erosion resistant casting. Therefore, the screw pump 60 and the die casting apparatus including the same can be provided at a lower cost than when all the liquid contact parts are made of silicon nitride.

  Further, according to the screw pump 60, the two bearings 3 and 4 for supporting the outer rotor 2 and the bearing 6 for supporting an intermediate portion of the inner rotor 1 are formed by a slip using the molten metal M, which is an ambient fluid, as a lubricating fluid. Among the two sliding bearings 3 and 4 that support the outer rotor 2, a sliding bearing 4 provided at an upper portion and a sliding bearing 6 that supports a middle part of the inner rotor 1 are formed on the inner peripheral surface along the axial direction. Respectively, and a labyrinth groove 43 formed in a plurality of stages on the inner peripheral surface along the circumferential direction, so that not only the outer rotor 2 and the inner rotor 1 are rotatably supported, but also a plurality of stages. By the labyrinth groove 43, the sealing property can be more suitably secured. Therefore, the pulsation is extremely low, and it is more suitable for making a pouring device capable of supplying a high-precision quantitative supply.

Further, according to the screw pump 60, the pump body 30 is further provided with an extended support structure for supporting the pump body 30 at a position extended from the servo motor 22 above the pot 80 toward the pot 80, so that the pump is extended at the position extended toward the pot. The main body 30 can be supported.
In particular, the extension support structure includes an intermediate frame 7 made of a erosion-resistant casting formed in a hollow cylindrical shape and interposed between the housing 31 and the frame 21 on which the servomotor 22 is mounted. , An intermediate shaft 10 that connects the base end 1c of the inner rotor 1 to the drive shaft 22m of the servomotor 22, and the frame 21, the housing 31, and the intermediate frame 7 are axially pressed to support each other. The inner rotor 1 is rotatably supported at the lower end of the intermediate frame 7 via a sliding bearing 6 made of silicon nitride. Therefore, the pump body 30 can be supported at a position extended toward the pot 80 by the extended support structure made of the erosion resistant casting. Therefore, it is suitable for forming an extended support structure that does not involve sliding with a relatively inexpensive erosion-resistant casting.

  The inner rotor 1 is connected to the drive shaft 22m via the intermediate shaft 10, and the base end 1c of the inner rotor 1 and the distal end 10s of the intermediate shaft 10 are connected by a tapered connection structure using a connection piece 8. Therefore, even if the wetted portion including the pump body 30 is exposed to, for example, a molten metal of 700 ° C. or more, the misalignment due to the difference in thermal expansion between both the inner rotor 1 and the intermediate shaft 10 is reduced by the taper between the intermediate shaft 10 and the inner rotor 1. It can be absorbed by the shape and the elastic force of the spring member 16 made of silicon nitride, which urges both end surfaces in the separating direction. Therefore, it is excellent as a connection structure of the drive shaft of the screw pump 60 used as a pouring device.

  Further, according to the screw pump 60, the two bearings 3 and 4 for supporting the outer rotor 2 are provided on the cylindrical outer peripheral surface with a tapered outer surface 45 whose diameter is reduced downward from the middle part in the axial direction to the lower end part. , 55, and the sliding bearing 6 that supports the intermediate portion 1b of the inner rotor 1 has a cylindrical outer peripheral surface having a tapered outer surface 65 whose diameter decreases upward from an intermediate portion in the axial direction to an upper end portion. On the inner peripheral surfaces of the housing 31 and the intermediate housing 13 into which these bearings 3, 4, and 6 are fitted, corresponding tapered inner surfaces 9n, 13n, and 7n are formed to provide a self-aligning structure by concave steps. Therefore, even when a gap is formed due to a difference in thermal expansion between the fitting parts of the liquid contact parts, the taper outer surface 45 of each of the bearings 3, 4, and 6 made of silicon nitride is caused by the discharge pressure applied inside the housing 31. , 55, 5, each of the tapered inner surface 9n of melting loss resistance cast iron housing 31 and the intermediate frame 7, 13n, pressed against the 7n, it is possible to self-centering of the outer rotor 2 and the inner rotor 1 axis of rotation. Therefore, according to this screw pump 60, it is more suitable as a uniaxial eccentric screw pump for transferring molten metal.

  As described above, according to the uniaxial eccentric screw pump 60 for transferring molten metal and the die casting apparatus including the same according to the present embodiment, the molten metal is pressure-fed in a closed circuit while securing the quantitativeness of molten metal supply. Can be. In addition, the uniaxial eccentric screw pump according to the present invention and the die casting apparatus including the same are not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. is there.

  For example, in the above-described embodiment, among the liquid contact parts immersed in the molten metal, at least a plurality of bearings 3 and 4 supporting the inner rotor 1, the outer rotor 2 and the outer rotor 2, which are liquid contact parts with sliding, are formed of silicon nitride. However, the present invention is not limited to this, and instead of silicon nitride, it can be formed of another ceramic material having heat resistance and thermal shock resistance capable of maintaining required mechanical strength.

1 inner rotor 2 outer rotor 3, 4 sliding bearing (bearing)
5 Upper housing (housing)
6 plain bearings (bearings)
7 Intermediate frame 8 Connecting piece 9 Lower housing (housing)
9a Suction port 10 Intermediate shaft 11 Connecting rods 12, 14, 15 Fixed key 13 Intermediate housing (housing)
Reference Signs List 16 spring member 17 rod fixing bolt 18 disk spring washer 19 bearing for high temperature environment 20 coupling shaft 21 frame 22 servo motor (motor)
22m Drive shafts 23, 24, 25 Fixed key 30 Pump body 31 Housing 41 Lubrication groove 43 Labyrinth groove 60 Uniaxial eccentric screw pump 70 for transferring molten metal Casting apparatus main body 71 Mold 72 Sleeve 73 Plunger 74 Pouring tube 80 Pot 90 Control unit M molten metal (molten metal)

Claims (6)

A housing in which an axis is vertically arranged, an outer rotor rotatably supported via a plurality of bearings vertically arranged in the housing and having a female screw-shaped inner surface, and a male screw-shaped helical portion in the outer rotor An inner rotor that is interpolated and has its base end connected to the drive shaft of the motor, and the inner rotor performs an eccentric motion while rotating with respect to the axis of the outer rotor, so that the molten metal sucked from the suction port A single-axis eccentric screw pump for transferring molten metal for transferring
The suction port is formed at a lower portion of the housing and at a position to be immersed in a molten metal in a molten metal pot,
Of the wetted parts immersed in the molten metal, the inner rotor, which is a wetted part with sliding, a plurality of bearings supporting the outer rotor and the outer rotor are formed of a ceramic material having heat resistance and thermal shock resistance,
A uniaxial eccentric screw pump for transferring molten metal, wherein the housing, which is a liquid contact part that does not involve sliding, of the liquid contact part immersed in the molten metal is formed of a erosion resistant casting.   The uniaxial eccentric screw pump for transferring molten metal according to claim 1, wherein the ceramic material is silicon nitride. Further provided is an extension support structure for supporting the uniaxial eccentric screw pump at a position extended from the upper motor to the pot side,
The extension support structure includes:
An intermediate frame made of a erosion-resistant casting formed in a hollow cylindrical shape and interposed between the frame on which the motor is mounted and the housing,
An intermediate shaft that is inserted into the intermediate frame and connects a base end of the inner rotor and a drive shaft of the motor;
The frame, the housing and the intermediate frame having a plurality of connection rods made of erosion resistant casting to support and support each other in the axial direction,
The uniaxial eccentric screw pump for transferring molten metal according to claim 1 or 2, wherein the inner rotor is rotatably supported at a lower part of the intermediate frame via a bearing made of the ceramic material. The plurality of bearings that support the outer rotor and the bearing that supports an intermediate portion of the inner rotor are cylindrical slide bearings that use an atmospheric fluid as a lubricating fluid,
The plurality of bearings that support the outer rotor each have a tapered outer surface that is reduced in diameter from the middle part in the axial direction to the lower end part on the cylindrical outer peripheral surface,
The slide bearing supporting the middle portion of the inner rotor has a tapered outer surface on an outer peripheral surface of a cylindrical shape whose diameter decreases upward from the middle portion in the axial direction to the upper end portion,
The housing has a lower housing having the suction port, an intermediate housing, and an upper housing having the discharge port in this order from the lower side to the upper side,
The lower housing and the intermediate housing have an inner peripheral surface radially opposed to a plurality of bearings supporting the outer rotor, a cylindrical inner surface slidably contacting the outer peripheral surface and the tapered outer surface of each bearing, and a diameter increasing upward. Each having a tapered inner surface,
The intermediate frame is reduced in diameter toward an inner peripheral surface that radially opposes a slide bearing that supports a middle portion of the inner rotor, an inner cylindrical surface that slides on the outer peripheral surface and the tapered outer surface of the slide bearing, and upward. 4. The pump according to claim 3, wherein the pump has a tapered inner surface. Cold chamber type casting apparatus main body, uniaxial eccentric screw pump vertically arranged so that the suction port is immersed in the molten metal in the pot, and pouring that connects the sleeve of the casting apparatus main body with the discharge port. With a tube ,
Examples uniaxial eccentric screw pump, die casting apparatus characterized by having a uniaxial eccentric screw pump for molten metal transport according to any one of claims 1-4. The single-axis eccentric screw pump includes a servomotor that rotationally drives the inner rotor, and a control unit that controls the servomotor,
The die casting apparatus according to claim 5, wherein the control unit controls a supply amount of the molten metal by the uniaxial eccentric screw pump based on a supply amount of the molten metal by a plunger of the casting apparatus body.

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