JPH08332559A - Pressure casting method and apparatus thereof - Google Patents

Abstract

PURPOSE: To make an apparatus compact and to reduce an equipment cost by acting a pressurizing pin with explosive force of combustible gas or thermal expansive force of incombustible gas in the pressure casting apparatus. CONSTITUTION: A die 12 of the pressure casting apparatus 10 is constituted with a fixed die 12s, movable die 12m, upper slide core 12u and lower slide core 12d and the high molten metal is supplied into a cavity 14 in the die 12 from an injection part at a prescribed timing. The pressurizing pin 15 is inserted into a through-hole 12k of the fixed die 12s under condition capable of sliding in an axial direction and the molten metal in the cavity 14 is pushed at the high pressure after filling up the molten metal into the cavity 14. Mixed gas in a tank 18t is supplied into a combustion chamber 17f of a high pressure cylinder 17y by opening a high pressure shut-off valve 18v of a mixed gas supplying part 18 to work a press-in pump 18p, and an ignition plug 19b is ignited and a driving rod 17r of the high pressure cylinder 17y pushes the pressurizing pin 15 into the cavity 14 by the explosive force of the mixed gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure casting method and a pressure casting apparatus in which a molten metal is filled in a cavity of a mold and a predetermined portion of the molten metal is pressed by a pressure pin while the molten metal is solidified. Regarding

[0002]

2. Description of the Related Art A conventional pressure casting apparatus related to this is described in Japanese Patent Application No. 4-166802. According to the pressure casting apparatus, the hydraulic pin is used to press the molten metal by operating the pressing pin at a predetermined timing.

[0003]

However, according to the system in which the pressurizing pin is operated by the hydraulic cylinder, a high-pressure pipe for guiding high-pressure oil from the hydraulic pump to the hydraulic cylinder is required. Since the high-pressure pipe requires high strength, it becomes heavy and the pipe equipment becomes large. Further, if the pipe is to be stored in the mold, the mold becomes large.
Further, a high-pressure hydraulic pump is required, and in order to secure a stable hydraulic pressure when there are a plurality of pressurizing pins, a hydraulic pump is required for each hydraulic cylinder. For this reason, there is a problem that the equipment cost also becomes high. The technical problem of the present invention is to reduce the size and cost of the casting equipment by making it possible to omit the high-pressure pipes and the like that lead to an increase in the size of the casting equipment and the hydraulic pump that causes a high cost. It is a thing.

[0004]

[Means, actions, and effects for solving the problems]

[Means according to Claim 1 for Solving the Problems] The problems described above are solved by a pressure casting method having the following features. That is, the pressure casting method according to claim 1, wherein the molten metal is filled in the cavity of the mold, and a predetermined portion of the molten metal is pressed by a pressure pin in the process of solidifying the molten metal, It is characterized in that the pressure pin is operated by a force resulting from the expansion of gas. [Operation of the invention described in claim 1] According to the present invention,
Since this is a method of operating the pressurizing pin with a force resulting from the expansion of the gas, it is sufficient to enclose the gas in the actuator, and a mechanism for pressurizing the gas or a mechanism for pumping the gas is unnecessary. For this reason, the hydraulic pump, high-pressure pipe, and the like, which have been conventionally required when operating the pressurizing pin with the hydraulic cylinder, are unnecessary. [Effect of the invention described in claim 1] According to the present invention,
Unlike the conventional hydraulic cylinder, high pressure pipes, hydraulic pumps, etc. are not required, so that the casting equipment can be made compact and the cost can be reduced.

[Means according to claim 2 for solving the problem] Further, in the pressure casting apparatus according to claim 2, the molten metal is filled in the cavity of the mold, and the molten metal is solidified during the solidification process. In the pressure casting apparatus for pressurizing a predetermined portion of the pressure pin with a pressure pin, a pressing mechanism having a structure for operating the pressure pin by a force caused by expansion of gas is characterized. [Operation of the invention described in claim 2] According to the present invention,
Since the pressing mechanism operates the pressure pin with a force resulting from the expansion of the gas, the invention described in claim 1 can be implemented by the pressure casting device according to the present invention. [Effect of the invention described in claim 2] According to the present invention, the same effect as the invention described in claim 1 can be obtained.

[Means for Solving the Problems] A pressure casting apparatus according to claim 3 is the pressure casting apparatus according to claim 2, wherein the pressing mechanism is a combustible gas. The pressure pin is operated by the explosive force of. [Operation of the invention described in claim 3] According to the present invention,
Since the pressing mechanism operates the pressure pin with the explosive force of the combustible gas, the pressure pin can be operated at a desired timing by controlling the ignition timing. [Effect of the invention described in claim 3] According to the present invention,
In order to freely control the operation timing of the pressure pin,
It becomes possible to pressurize the molten metal at an appropriate time. Therefore, it is possible to effectively prevent the occurrence of shrinkage cavities and the like.

[Means according to claim 4 for solving the problem] Further, the pressure casting apparatus according to claim 4 is the pressure casting apparatus according to claim 2, wherein the pressing mechanism is a noncombustible gas. The pressure pin is operated by the thermal expansion force of. [Operation of the invention described in claim 4] Also in the present invention, the pressurizing pin can be operated at a desired timing by controlling the heating timing of the noncombustible gas. Further, since the gas does not burn, exhaust gas etc. does not occur. Further, the gas after the thermal expansion can be reused by collecting and cooling it. [Effect of the invention described in claim 4] According to the present invention,
The effect similar to that of the invention of claim 1 is obtained, and exhaust gas and the like are not generated, which is environmentally advantageous. Further, since the noncombustible gas can be recovered and reused, the cost can be reduced.

[0008]

【Example】

[First Embodiment] The pressure casting method and apparatus according to the first embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Here, FIG. 1 and FIG. 2 are vertical cross-sectional views of a mold portion of the pressure casting apparatus 10 according to the present embodiment. The die 12 of the pressure casting apparatus 10 includes a fixed die 12s and a movable die 12
m, upper slide core 12u and lower slide core 12
A cavity 14 for forming a casting is formed in the mold 12 in a state of being clamped by a mold opening / closing mechanism (not shown). Here, the central portion of the cavity 14 is a thick-walled molded portion A. It should be noted that the high-pressure molten metal is supplied to the cavity 14 at a predetermined timing from an injection unit (not shown).

The fixed mold 12s includes the thick-walled molding portion A.
A pressure pin 15 is horizontally mounted at a position where the molten metal can be pressurized. The pressure pin 15 is inserted in the through hole 12k of the fixed mold 12s in a state of being slidable in the axial direction, and the base end portion 15m thereof is connected to the drive rod 17r of the pressing mechanism 17 by the connecting member 16. . Further, the fixed mold 12s is formed with a circular recess 12h around the through hole 12k so that the connecting member 16 does not come into contact with the fixed mold 12s while moving in the axial direction.

The pressing mechanism 17 is a mechanism for pushing the pressurizing pin 15 into the cavity 14 with a high pressure of 50 MPa to 30 MPa after the cavity 14 is filled with the molten metal, and the high pressure cylinder 17y and the mixed gas supply unit 18 are provided. And an ignition unit 19. The high-pressure cylinder 17y is fixed to the outer surface of the fixed mold 12s while being held coaxially with the pressure pin 15 by a cylinder mount 17e, and the drive rod 17r, which is the piston rod of the high-pressure cylinder 17y, is As described above, the pressurizing pin 15 is connected by the connecting member 16. Further, a circular recess 17h is formed in the cylinder mount 17e so as to be continuous with the circular recess 12h of the fixed mold 12s, and the cylinder mount 17e is formed while the connecting member 16 moves in the axial direction.
It does not come into contact with e.

The mixed gas supply unit 18 includes a tank 18t for storing a combustible mixed gas such as hydrogen, propane gas and oxygen, a press-fit pump 18p for sending the mixed gas to the high pressure cylinder 17y, and a high pressure cutoff valve 18v. The tank 18t and the press-fitting pump 18p are mounted on a carriage (not shown) and movable. The high pressure cutoff valve 18v is attached to the high pressure cylinder 17y, and the combustion chamber 1 of the high pressure cylinder 17y is
7f and the press-fitting pump 18p can be maintained in a communication state or a blocking state. Then, the high-pressure shutoff valve 18v is opened and the press-fitting pump 18p is operated, so that the mixed gas in the tank 18t becomes high-pressure cylinder 17y.
Is supplied to the combustion chamber 17f. Further, in this state, the high pressure cutoff valve 18v is closed, whereby the combustion chamber 1
A mixed gas is sealed in 7f.

Here, the high pressure cutoff valve 18v and the press-fitting pump 18p are adapted to be operated based on an operation signal from the control panel 11. Further, pressure information of the tank 18t, opening / closing information of the high-pressure shutoff valve 18v, operation information of the press-fitting pump 18p, etc. are input to the control panel 11. Further, the combustion chamber 17f of the high pressure cylinder 17y
An ignition plug 19b that constitutes the ignition portion 19 is attached to the control panel 11, and an ignition signal is output from the control panel 11 to the ignition plug 19b at a predetermined timing. With this structure, the mixed gas is exploded while the spark plug 19b is ignited in a state where the mixed gas is sealed in the combustion chamber 17f of the high-pressure cylinder 17y, and the explosive force causes the drive rod 17 of the high-pressure cylinder 17y to explode.
The r pushes the pressure pin 15 into the cavity 14. Exhaust gas after the explosion is generated by the operation of the switching valve (not shown) of the press-fitting pump 18p.
It is operated in a state where it does not communicate with the
When v is released, it is discharged to the outside.

Next, the pressure casting method will be described while explaining the operation of the pressure casting apparatus 10 according to the present embodiment. First, a trolley in which a tank 18t for storing a mixed gas of hydrogen, propane gas, oxygen and the like and a pressurizing pump 18p are installed is installed on the side of the pressurizing casting apparatus 10, and the pressurizing pump 18p and the high pressure cylinder 17y have a high pressure. The shutoff valve 18v is connected. Next, the mold opening / closing mechanism of the pressure casting apparatus 10 operates to clamp the mold 12. In the state where the mold is clamped, as shown in FIG. 1, the tip end surface of the pressure pin 15 becomes continuous with the molding surface of the cavity 14.

When the preparation for casting is completed in this way,
High-pressure molten metal is pressed into the cavity 14 of the mold 12 from the injection part. Further, the high-pressure shutoff valve 18v of the high-pressure cylinder 17y is opened, and the press-fitting pump 18p is operated to supply the mixed gas from the tank 18t to the combustion chamber 17f of the high-pressure cylinder 17y. Next, by closing the high pressure shutoff valve 18v, the mixed gas is sealed in the combustion chamber 17f of the high pressure cylinder 17y.

A predetermined time has passed since the molten metal was filled in the cavity 14, and an ignition signal is output from the control panel 11 to ignite the ignition plug 19b in the process in which the molten metal solidifies from the surface side. As a result, the mixed gas sealed in the combustion chamber 17f of the high-pressure cylinder 17y explodes, and the explosive force causes the drive rod 17r of the high-pressure cylinder 17y to move the pressurizing pin 15 into the cavity 14 as shown in FIG. It will be pushed. As a result, the thick portion A of the molten metal in the semi-solidified state is 50 MPa to 30 MPa by the pressure pin 15.
The high pressure of a is locally applied to crush the bubbles and the like in the molten metal and supplement the solidification shrinkage of the molten metal to prevent defects such as shrinkage cavities.

When the molten metal is wholly solidified and the molding of the cast product is completed, the mold 12 is opened and the cast product is taken out. Further, the press-fitting pump 18p is operated by a switching valve (not shown) so that the tank 18t
Operates in a state where it does not communicate with the high pressure cutoff valve 18v
Is opened, the exhaust gas in the combustion chamber 17f of the high pressure cylinder 17y is discharged to the outside. Here, since the mixed gas contains hydrogen and oxygen, when it explodes, water is generated, so that soot and the like are less likely to be scattered, so that the deterioration of the environment can be prevented to some extent.

As described above, according to the pressure casting method of this embodiment, the pressure pin 15 is generated by the force caused by the explosion of the mixed gas.
Is a method of operating. Therefore, unlike the conventional case, the hydraulic pump, the high-pressure pipe, and the like, which are required when the pressure pin is operated by the hydraulic cylinder, are not required. Further, since the tank 18t and the pressure pump 18p are mounted on a dolly and movable, they may be installed on the side of the pressure casting device 10 when used. Therefore, the pressure casting apparatus can be made compact and the cost can be reduced. Further, by controlling the ignition timing, the pressurizing pin 15 can be operated at a desired timing, so that it is possible to effectively prevent the occurrence of shrinkage cavities and the like. In the present embodiment, the high pressure cutoff valve 18v is used to seal the mixed gas in the high pressure cylinder 17y, but the pressure control valve with a cutoff function is used to adjust the pressure of the mixed gas in the combustion chamber 17f. can do. This allows the explosive power to be adjusted.

[Second Embodiment] Next, a pressure casting method and an apparatus therefor according to a second embodiment of the present invention will be described with reference to FIGS. 3 and 4. Here, FIG. 3 and FIG. 4 are vertical cross-sectional views of the mold portion of the pressure casting apparatus 20 according to this embodiment. The pressure casting apparatus 20 according to the present embodiment is one in which the incombustible gas is rapidly thermally expanded and the pressing pin 25 is actuated by the force, and the other structure is the pressure casting apparatus 10 according to the first embodiment. Is the same as.

The pressing mechanism 27 for operating the pressurizing pin 25 is composed of a high pressure cylinder 27y, a non-combustible gas supply section 28 and a heating section 29. Further, the non-combustible gas supply unit 28 includes a tank 28t for storing non-combustible gas such as carbon dioxide and nitrogen, a press-fit pump 28p for sending the non-combustible gas to the high-pressure cylinder 27y, and a high-pressure shutoff valve 28v. The tank 28t and the press-fitting pump 28p are mounted on a carriage (not shown) and movable. Here, the tank 28t is equipped with a cooling device (not shown) for cooling the recovered incombustible gas.

The high-pressure shutoff valve 28v is mounted on the high-pressure cylinder 27y.
The heating chamber 27f of 7y and the press-fitting pump 28p can be maintained in a communicating state or a blocking state. Then, the high-pressure shutoff valve 28v is opened and the press-fitting pump 28
When p operates, the non-combustible gas in the tank 28t is supplied to the heating chamber 27f of the high pressure cylinder 27y. Further, in this state, the high pressure cutoff valve 28v is closed, so that the heating chamber 27f is sealed with a non-combustible gas.

Further, the heating chamber 27f of the high-pressure cylinder 27y is provided with a heater 29b constituting a heating section 29, and a heating signal is output from the control panel 21 to the heater 29b at a predetermined timing. It is like this. With this structure, the heater 2 is provided in a state where the non-combustible gas is sealed in the heating chamber 27f of the high pressure cylinder 27y.
By energizing 9b, the non-combustible gas expands, and the expansion force of the non-combustible gas drives the drive rod 27 of the high-pressure cylinder 27y.
The r pushes the pressure pin 25 into the cavity 24. The incombustible gas used to drive the high pressure cylinder 27y is supplied to the tank 28 by the press-fitting pump 28p.
After returning to t, it is cooled by the cooling device and used in the next casting.

Next, the pressure casting method will be described while explaining the operation of the pressure casting apparatus 20 according to this embodiment. First, a trolley on which a tank 28t for storing non-combustible gas such as carbon dioxide and nitrogen and a pressure pump 28p are mounted is installed on the side of the pressure casting device 20, and the pressure pump 28
p and the high pressure cutoff valve 28v of the high pressure cylinder 27y are connected. Next, the mold opening / closing mechanism of the pressure casting device 20 operates to clamp the mold 22.

When the preparation for casting is completed in this way,
High-pressure molten metal is pressed into the cavity 24 of the mold 22 from the injection part. Further, the high-pressure shutoff valve 28v of the high-pressure cylinder 27y is opened, and the press-fitting pump 28p is operated to supply the non-combustible gas from the tank 28t to the heating chamber 27f of the high-pressure cylinder 27y. Next, by closing the high pressure shutoff valve 28v, the high pressure cylinder 27y
A non-combustible gas is sealed in the heating chamber 27f.

The heater 29b is energized in a process in which a predetermined time has elapsed since the molten metal was filled in the cavity 24 and the molten metal solidified from the surface side. As a result, the non-combustible gas sealed in the heating chamber 27f of the high-pressure cylinder 27y expands, and the expansion force causes the drive rod 27r of the high-pressure cylinder 27y to move the pressurizing pin 25 into the cavity 24 as shown in FIG. Will be pushed into.
As a result, the thick portion A of the molten metal in the semi-solidified state becomes the pressure pin 25.
As a result, local pressure is applied at a high pressure of 50 MPa to 30 MPa, air bubbles and the like in the molten metal are crushed, and solidification shrinkage of the molten metal is compensated for, and defects such as shrinkage cavities are prevented.

When the molten metal is wholly solidified and the molding of the cast product is completed, the mold 22 is opened and the cast product is taken out. Further, the press-fitting pump 28p operates to open the high pressure cutoff valve 28v, whereby the non-combustible gas in the heating chamber 27f of the high pressure cylinder 27y is returned to the tank 28t and cooled.

As described above, in this embodiment, the pressurizing pin can be operated at a desired timing by controlling the heating timing of the noncombustible gas, so that the occurrence of shrinkage cavities can be effectively prevented. become able to. further,
Since the gas does not burn, exhaust gas is not generated, which is environmentally advantageous. Further, the gas after the thermal expansion is recovered and reused by cooling, so that the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a mold portion of a pressure casting device according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of a die portion of the pressure casting device according to the first embodiment of the present invention.

FIG. 3 is a vertical cross-sectional view of a mold part of a pressure casting device according to a second embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view of a die part of a pressure casting device according to a second embodiment of the present invention.

[Explanation of symbols]

 12 Mold 14 Cavity 15 Pressurizing Pin 17 Pressing Mechanism 17y High Pressure Cylinder (Pressing Mechanism) 17r Drive Rod (Pressing Mechanism) 17f Combustion Chamber (Pressing Mechanism) 18v High Pressure Shutoff Valve (Pressing Mechanism) 18p Press-fitting Pump (Pressing Mechanism) 18t Tank (Pressing mechanism) 19b Spark plug (Pressing mechanism)

Claims (4)

[Claims] 1. A pressure casting method in which a molten metal is filled in a cavity of a mold and a predetermined portion of the molten metal is pressed by a pressure pin in a process of solidifying the molten metal, wherein the pressure pin is used to expand gas. A pressure casting method, characterized in that the pressure casting method is operated by a force caused by the pressure. 2. A pressure casting apparatus in which a molten metal is filled in a cavity of a mold and a predetermined portion of the molten metal is pressed by a pressure pin in the process of solidifying the molten metal, the force is caused by expansion of gas, A pressure casting apparatus having a pressing mechanism having a structure for operating a pressing pin. 3. The pressure casting apparatus according to claim 2, wherein the pressing mechanism operates the pressure pin by the explosive force of the combustible gas. 4. The pressure casting apparatus according to claim 2, wherein the pressing mechanism operates the pressure pin by a thermal expansion force of noncombustible gas.