JP2001030050A - Device for sealing shaft part in apparatus used for using molten metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a good sealness by a simple means and to improve the durability of a sealing part. SOLUTION: A screw 13 is rotatably arranged in a casing 7 in a semi-molten metal continuous supplying device for supplying the molten metal 1 and a sealing member 17 is disposed in the casing 7 at rotary driving part side. Further, near the sealing member 17, a sealing part temp. control means 18 for holding the supplied molten metal 1 to the semi-solidified state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shaft sealing device for equipment using molten metal such as a blast furnace and a metal injection molding machine.

[0002]

2. Description of the Related Art In general, an injection molding machine is used to produce a product having a desired quality and shape from a metal material such as a molten aluminum alloy or a magnesium alloy.
The injection molding machine includes a supply hopper in an inert gas atmosphere for storing a metal material, an injection machine communicating with the supply hopper via a conduit, and a mold provided with a cavity communicating with the inside of the injection machine. A rotatable kneading screw is disposed inside the cylinder of the injection machine. In order to manufacture a product using such an injection molding machine, first, an ingot-shaped metal material is heated and pulverized, supplied from a supply hopper to a cylinder of the injection machine through a conduit, and then kneaded by the injection machine. The screw is driven to rotate, the supplied metal material is agitated into fine particles, and is stored in front of the cylinder. Then, when a certain amount of the metal material has accumulated, the kneading screw is strongly pushed out, and the molten metal material is pressed into the cavity of the mold from the tip of the injection machine to obtain an alloy product.

By the way, at the rear end of the cylinder of the injection machine,
A sealing device 51 as shown in FIG. 3 is provided. The sealing device 51 is provided for the purpose of, for example, blocking the metal material supplied into the cylinder 52 from the outside air at the rear end of the cylinder and preventing the metal material from leaking to the outside. And a gap formed between the mixing screw 53 and the shaft 53a of the kneading screw 53 are sealed. Therefore, the seal device 51 includes a seal case 54 attached to the end of the cylinder 52, a seal holder 56 disposed in a space 55 in the seal case 54, and the seal holder 56 and the shaft shaft 53 a. The seal holder 56 includes a rotary slide seal 57 provided and a pair of O-rings 58 and 59 provided between an outer wall surface of the seal holder 56 and an inner wall surface of the seal case 54.
Are supported in a floating manner in the space 55.
According to such a sealing device 51, the kneading screw 53
Even if the shaft shaft portion 53a of the shaft 5a swings in the radial direction, the seal holder 56 follows, so that the sealing effect is not impaired, and the rotary slide seal 57 and the O-ring 5
8,59 will not be overstressed,
The durability of these members can be improved.

[0004]

However, in the above-described conventional sealing device 51, the molten metal in the cylinder 52 is sealed by the rotary sliding seal 57 and the O.D.
Since the sealing is directly performed by the rings 58 and 59, particularly in the case of a molten aluminum alloy having a low viscosity, the molten aluminum alloy easily enters a small gap of the sealing portion, and has a problem that a leak amount increases. When the molten metal leaking from the seal enters the bearing that supports the shaft portion 53a, the device may be damaged. In addition, among the metallic materials supplied into the cylinder 52, the molten aluminum alloy is particularly active, so that not only the gap of the seal portion but also the rotary slide seal 57 and the O-ring 58,
Even for 59 itself, it is necessary to use a material having extremely low reactivity to increase the corrosion resistance, resulting in a problem that the cost is increased. The sealing device 51
In the conventional sealing device including the method described above, the temperature of the molten metal is not controlled near the seal portion.

The present invention has been made in view of such circumstances, and has as its object to provide a molten metal capable of maintaining good sealing properties by simple means and improving the durability of the sealing portion. An object of the present invention is to provide a shaft sealing device for a used device.

[0006]

In order to solve the problems of the prior art, according to the present invention, a drive shaft is rotatably provided on a casing of a device to be used to which molten metal is supplied, and the drive shaft is provided on the rotary drive side. And a temperature control means for maintaining the supplied molten metal in a semi-solid state in the vicinity of the seal member.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments. Here, FIG. 1 is a configuration diagram of a semi-molten metal continuous supply device to which a shaft sealing device of a device using molten metal according to an embodiment of the present invention is applied, and FIG. 2 is a cross-section showing a seal portion of the continuous supply device. FIG.

As shown in FIG. 1, a continuous supply apparatus for semi-molten metal according to an embodiment of the present invention comprises, for example, silicon (Si).
Supply means 3 for supplying molten metal 1, which is an alloy material such as aluminum and aluminum (Al), into inlet 2 a of cylinder 2
A cylinder portion temperature control means 4 for heating or cooling the outer peripheral wall of the cylinder 2 to adjust the cylinder temperature so that the molten metal 1 supplied into the cylinder 2 becomes semi-molten metal; And a detecting means 6 for detecting the molten state of the semi-molten metal stirred and transported to the outlet 2b of the cylinder 2 continuously.

The cylinder 2 is provided inside a casing 7 constituting a continuous supply device, and is formed in a tapered cylindrical shape positioned substantially horizontally. An inlet 2a communicating with the supply means 3 is provided on the upper wall on the upstream side of the cylinder 2, and an outlet 2b communicating with the cooling device (molding device) 8 is provided on the distal end on the downstream side. Is provided. The supply means 3 is provided with a molten metal 1 which has been melted and conveyed by an external heating device (not shown).
Hopper-shaped holding furnace 9 for storing the gas, a heating heater 10 disposed around the holding furnace 9 for keeping the temperature of the molten metal 1 in the holding furnace 9 constant, and an integrated heater at the bottom of the holding furnace 9. And a conduit 9 a communicating with the holding furnace 9 and the cylinder 2. Therefore, the molten metal 1 in the holding furnace 9 is sequentially fed from the bottom of the holding furnace 9 to the inlet 2a of the cylinder 2 via the conduit 9a so that air is not entrained in the molten metal 1. .

The cylinder temperature control means 4 is provided along the axial direction on the outer circumference of the cylinder 2 and at an intermediate portion between the inlet 2a and the outlet 2b, and is supplied into the cylinder 2. The molten metal 1 is configured to be once cooled to a solidus temperature or lower by supercooling. That is, the molten metal 1 in the molten metal state supplied from the holding furnace 9 is brought into a semi-molten state in the cylinder 2 by the temperature control means 4. By the way, when the molten metal is uniformly melted at a temperature equal to or higher than the liquidus temperature, the solid phase begins to crystallize when the temperature decreases and the liquidus temperature is reached. When the phases coexist and the temperature further decreases to a temperature below the solidus temperature, only the solid phase is formed and the solidification is completed. For this reason, the cylinder section temperature control means 4 includes the heater 11 and the cooling blower 1.
2, a melting portion (liquidus temperature + α) above the liquidus temperature located on the inlet 2a side and a solidus temperature located in the middle of the inlet / outlets 2a and 2b. The following partial solid phase generating part (solidus temperature-α, supercooling) and the solid-liquid phase kneading part (solidus to liquid phase) located at the outlet side and above the solidus temperature and below the liquidus temperature (Linear temperature range).

The stirring and transferring means 5 has a screw (drive shaft) 13 rotatably provided on the casing 7. The screw 13 is rotatably supported in the cylinder 2 and is provided outside the casing 7. Is configured to be rotationally driven by the rotational drive device 14 provided in the first embodiment. The screw 13 pulverizes dendrites (dendritic crystals) in the semi-molten metal in the cylinder 2 into particles, reduces the solidification shrinkage, reduces shrinkage cavities, improves the mechanical properties of the material, and has fluidity. It is provided in the cylinder 2 in order to extrude the deposited high quality semi-molten metal. Accordingly, the screw 13 has a cylindrical screw body 13a, and a plurality of screw grooves 15 for stirring and transferring the semi-molten metal are arranged at intervals in the axial direction on the outer peripheral surface of the screw body 13a. ing.

On the other hand, the base end of the screw 13 is connected to a rotary drive device 14 via a screw shaft 13b, and a through hole 16 through which the screw shaft 13b is inserted is formed in the upstream end wall of the casing 7. Has been established. Therefore,
On the upstream end wall of the casing 7 located on the side of the rotation drive unit, a seal member 17 for airtightly partitioning from the outside is provided, and near the seal member 17 (outer periphery), the inside of the cylinder 2 is provided. A seal portion temperature control means 18 for holding the supplied molten metal 1 in a semi-solid state is provided, and the seal member 17 and the seal portion temperature control means 1 are provided.
8 prevents leakage of the molten metal 1 from the through hole 16 and entrapment of air. The seal member 17 is formed of hexagonal boron nitride (h-BN) having low reactivity with the molten metal 1 such as a molten aluminum alloy and solid lubricity in order to prevent erosion by the molten metal 1. Have been.

The seal portion temperature control means 18 is provided on the outer peripheral surface of the through-hole 16 on the outer side surface of the upstream end wall of the casing 7, and is provided near the seal member 17 by a temperature sensor (not shown). The temperature of the molten metal 1 is detected, and the temperature of the molten metal 1 is controlled by heating the molten metal 1 based on the detection signal. That is, the temperature of the molten metal 1 is raised or lowered by the seal portion temperature control means 18 to maintain the molten metal 1 in a semi-solid state to increase the viscosity,
The molten metal 1 itself is configured to be used as a sealing material, and a casing 7 located on the side of the rotation drive unit is provided.
Of the upstream end wall is maintained.

A discharge hole 19 is formed in the inside of the cylindrical sub-casing 7a positioned axially outside the seal member 17 so as to be inclined downward and communicate with the outside. The molten metal 1 that has flowed out through a gap with the screw shaft 13b is discharged to the outside through the discharge hole 19. In addition, a ring-shaped baffle plate 20 that protrudes in the radial direction is provided on the outer periphery of the screw shaft 13b located on the outer side in the axial direction of the seal member 17, and the baffle plate 20 allows the molten metal 1 to move in the axial direction. The movement is prevented, and the molten metal 1 is prevented from flowing to the bearing 21 supporting the screw 13. The bearing 21 is provided on the rotation drive device 14 side outside the baffle plate 20.

Further, a cylindrical sleeve 22 for protecting the screw shaft 13b from the molten metal 1 is fitted around an outer peripheral portion of the screw shaft 13b corresponding to the seal member 17, and the sleeve 22 is provided with a seal. It is arranged from the vicinity of the member 17 to the bearing 21. Therefore, the sleeve 22 is formed of ceramic (Si ₃ N ₄ ) having heat resistance. In addition, the melting state detecting means 6
As shown in FIG. 1, is provided at the outlet 2b of the cylinder 2. The detecting means 6 includes a temperature detecting means such as a thermocouple, and a solid phase of semi-molten metal using an ultrasonic sensor or an eddy current sensor. There is a rate detection means.

Next, in order to continuously extrude a semi-molten metal such as an aluminum alloy into the cooling device 8 by a continuous supply device to which the shaft sealing device according to the embodiment of the present invention is applied, as shown in FIG. The molten metal 1 stored in the holding furnace 9 of the means 3 is supplied from the inlet 2a into the cylinder 2 of the casing 7 through the conduit 9a, and the rotary drive 14
The screw 13 of the stirring and transferring means 5 is rotated.
The molten metal 1 supplied into the cylinder 2 is indicated by an arrow A in FIG.
While flowing as shown in the direction and being stirred by the screw 13 in the cylinder 2, it is sequentially transferred through the above three temperature distribution regions set by the cylinder temperature control means 4. On the other hand, the molten metal 1 in the cylinder 2 also flows in the direction of the upstream end wall of the casing 7 located on the rotation drive unit side as shown by the arrow B direction in FIG. Cooling by peripheral parts causes temperature drop,
The temperature is controlled by being heated by the seal portion temperature control means 18. Therefore, the molten metal 1 does not enter a completely solidified state or a completely molten state, but becomes a semi-solidified state having a high viscosity, and can be used as a sealing material. Accordingly, the molten metal 1 does not easily enter the gap between the seal member 17 and the sleeve 22. Moreover, the molten metal 1 that has leaked out of the seal member 17 is discharged from the discharge hole 1 of the sub-casing 7a.
9 does not flow out to the installation portion of the bearing 21 because it is discharged to the outside or dropped in the discharge hole 19 by being prevented from moving in the axial direction by the baffle plate 20.

Further, the supplied molten metal 1 is gradually cooled in a molten portion in the cylinder 2 and is supercooled for a short time to a temperature lower than the solidus temperature in the next partial solid phase generating portion to form a solid phase. In the next solid-liquid phase kneading section, a predetermined solid phase ratio is achieved by being maintained in the solidus to liquidus temperature range, and the solid phase and the liquid phase are kneaded and the solid phase is granularly dispersed. It becomes a semi-molten metal. At this time, a large number of crystal nuclei of the solid phase are crystallized at once by supercooling for a short time in the partial solid phase generating section, thereby preventing the dendrite from becoming coarse, and subsequently separating the dendrite in the solid-liquid phase kneading section. And a solid phase and a liquid phase are easily kneaded, and the solid-phase granular dispersion structure of the extruded semi-molten metal can be refined. Thereafter, the semi-molten metal is continuously extruded from the outlet 2b of the cylinder 2 toward the cooling device 8 by the screw 13, and is formed as an ingot 23 by the cooling device 8. At this time, the temperature and solid phase ratio of the semi-molten metal extruded from the outlet 2b of the cylinder 2 are detected by the molten state detection means 6, and the detection signal is fed back to the cylinder temperature control means 4 to reduce the cylinder temperature. If the adjustment is made, it becomes possible to more stably obtain a high-quality ingot 23. The ingot 23 is again brought into a semi-molten state by reheating, transported to an injection molding machine (not shown), and manufactured into a desired alloy product.

As described above, in the shaft seal device according to the embodiment of the present invention, the seal member 17 is provided on the upstream end wall of the casing 7 on which the rotary drive device 14 is provided, and A seal temperature control means 1 for holding the molten metal 1 in a semi-solid state having a high viscosity near the seal member 17.
Since the molten metal 1 is provided, the supplied molten metal 1 can be used as a sealing material, and the molten metal 1 is less likely to enter a gap between the seal member 17 and the sleeve 22 and can maintain good sealing performance. Even if the molten metal 1 enters the gap of the seal portion or the like, the molten metal 1 does not completely solidify, so that problems such as seizure do not occur. Moreover, the molten metal 1 in the semi-solid state has a lower activity than the completely molten state, does not easily erode the material of the seal member 17 and the like, and the seal member 17 is formed of hexagonal boron nitride. Since the sleeve 22 that covers the sleeve 13b is formed of ceramic, the life of the screw shaft 13b in the seal portion is extended. Further, according to the shaft sealing device according to the present embodiment, the molten metal 1 that has leaked to the outside of the sealing member 17 is discharged to the outside from the discharge hole 19 and is prevented from moving in the axial direction by the baffle plate 20. Therefore, it does not flow to the installation portion of the bearing 21 and the breakage of the continuous supply device can be prevented.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes may be made without departing from the gist of the present invention. What you get. For example, in the above-described embodiment, the shaft sealing device is applied to the semi-molten metal continuous supply device. However, the shaft sealing device is applied to other equipment using molten metal that requires the shaft sealing, such as a blast furnace or a metal injection molding machine. It is also possible.

[0020]

As described above, the shaft sealing device for a machine using molten metal according to the present invention has a drive shaft rotatably provided on a casing of the machine to which molten metal is supplied, and a casing on the side of the rotary drive unit. In addition to disposing a seal member, near the seal member is provided with a temperature control means for maintaining the supplied molten metal in a semi-solid state, so that good sealing properties are maintained with simple means, Erosion of the seal portion and the bearing portion by the molten metal can be reliably suppressed, and the durability and cost of the seal portion can be improved.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing a configuration of a semi-molten metal continuous supply device to which a shaft sealing device of a molten metal-using device according to an embodiment of the present invention is applied.

FIG. 2 is a sectional view showing a seal portion of the continuous supply device of FIG.

FIG. 3 is a sectional view showing a sealing device of a conventional injection molding machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Molten metal 2 Cylinder 3 Supply means 4 Cylinder temperature control means 5 Stirring transfer means 6 Melting state detection means 7 Casing 13 Screw 13b Screw shaft 14 Rotation drive device 16 Through hole 17 Seal member 18 Seal part temperature control means 19 Discharge hole 20 Baffle plate 21 Bearing 22 Sleeve

Claims (5)

[Claims] 1. A drive shaft is rotatably provided in a casing of a device to be used to which molten metal is supplied, a seal member is provided in a casing on the side of the rotary drive unit, and the supply shaft is provided near the seal member. A temperature control means for holding the molten metal in a semi-solid state in a shaft-sealing device for equipment using molten metal. 2. A casing positioned outside the seal member in the axial direction is provided with a discharge hole for molten metal, and an outer periphery of a drive shaft positioned outside the seal member in the axial direction is provided on the outer periphery of the molten metal in the axial direction. 2. The shaft sealing device for an apparatus using molten metal according to claim 1, further comprising a baffle for preventing movement. 3. The shaft sealing device for a machine using molten metal according to claim 1, wherein a sleeve is fitted to an outer peripheral portion of the drive shaft corresponding to the seal member. 4. The seal member is made of hexagonal boron nitride having low reactivity with molten metal and solid lubricity, and the sleeve is made of ceramic. Item 4. A shaft sealing device for a device using molten metal according to item 1 or 3. 5. The apparatus according to claim 1, wherein the apparatus using molten metal is a continuous supply apparatus for semi-molten metal.