JPS61215002A - Green sand molding equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an apparatus for molding a green mold in the production of pottery by supplying slurry made by dissolving mud with water into a mold at high pressure and dewatering it. .

[Conventional technology and its problems]

Fig. 5 shows a conventional green molding device, and in the figure, 2
8 consists of an upper mold 29 and a lower mold 30, with a molding space 3 inside.
This is a formwork for forming 1. Further, 32 is a pumping device that pumps the slurry into the molding space 31 through a pipe 33, and the pumping device 32 includes a slurry cylinder 34, a piston 35 attached to the inside of the slurry cylinder 34 so as to be able to move forward and backward, The hydraulic cylinder 36 drives the piston 35.

Further, 37 is a slurry tank that supplies slurry into the slurry cylinder 34 via a pipe 38.

Further, 39 is a hydraulic control circuit for driving the pressure feeding device 32, and the circuit 39 is connected to a hydraulic tank 40, a direction control valve 41, and pipes 42 and 43 that connect the direction control valve 41 and the hydraulic cylinder 36. It consists of

Also, to explain other configurations in the figure,
44 and 45 are a check valve and a slurry pressure gauge respectively attached to the pipe 33, 46 is a check valve attached to the pipe 38, and 4
7 is a hydraulic pressure gauge attached to the pipe 42, 48 is a sealing gasket, 49 is a hydraulic pump, and 50 is a pressure reducing valve.

With the above configuration, when the hydraulic cylinder 36 is driven and the piston 35 is raised, slurry is sucked into the slurry cylinder 34 from the slurry tank 37, and when the piston 35 is then lowered, the slurry is drawn from the slurry cylinder 34 into the formwork 28. The molding material is fed under pressure into the molding space 31 and pressurized.

Further, in the above device, in order to keep the pressure constant during pumping, the hydraulic control circuit 39 is controlled to keep the indicated pressure of the hydraulic pressure gauge 47 constant.

However, the sliding resistance of the sealing gasket 48 disposed on the sliding surfaces of the slurry cylinder 34 and piston 35 changes due to changes in temperature or the type of slurry, and the fact that the hydraulic fluid Since the viscosity changes due to temperature changes, the slurry pressure cannot be maintained accurately because the indication from the slurry pressure gauge 45 is constant.

The above-mentioned molding apparatus is sufficient for general green molds, but when high precision is required for green molds as in recent years, yields have been poor and production costs have increased.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a green molding apparatus that can solve the above problems.

[Means for solving problems]

In order to solve the above problems, in the present invention, a slurry pumping device in a green molding device is provided with a cylindrical body having an upper wall and a lower wall, and is slidably disposed inside the cylindrical body. A piston that forms a lower slurry space in the lower part of the piston, an electromagnet buried in the upper and lower parts of the piston, and an electromagnet buried in the upper and lower walls of the cylindrical body that mutually attract and repel the electromagnet in the piston. A pressure detection sensor for detecting the slurry pumping pressure is attached to the slurry pumping pressure, and a control device is further provided for controlling the magnetic force of the electromagnet based on a detection signal from the pressure detection sensor. .

〔Example〕

Hereinafter, a detailed explanation will be given based on an example shown in the attached drawings.

FIG. 1 shows the overall configuration of a green molding apparatus according to the present invention.

In the figure, 1 is a mold consisting of an upper mold 2 and a lower mold 3, and a green molding space 4 is formed inside.

Further, the formwork 1 is connected to a pressure feeding device 7 through a pipe 6 equipped with a check valve 5, and the pressure feeding device 7 is also connected to a slurry tank 10 through a pipe 9 similarly equipped with a check valve 8. .

In such a configuration, the present invention provides that the pressure feeding device 7 is configured to be driven by an electromagnet, and that the pressure feeding device 7 is driven by an electromagnet.
It is characterized by a configuration in which the operation is controlled by fluctuations in the pumping pressure of the slurry flowing into the green molding space 4 through the piping 6.

That is, as shown in FIG.
An upper wall 12 and an intermediate wall 1 are provided at the upper, middle and lower parts of the
3 and the lower wall 14 are integrally attached, an opening is provided in the intermediate wall 13, a piston 15 is provided slidably through the opening, and electromagnets M are installed at the upper and lower parts of the piston 15.
1 and M2 are buried, and electromagnets M3 and M4 are buried in the upper wall 12 and the lower wall 14 facing the upper and lower parts of the piston 15.
are buried respectively, and a packing 16 is further provided in the opening of the intermediate wall 13.

With this configuration, the electromagnets M1, M3 are attracted to each other, and the electromagnets M2. If M4 is made to repel each other, the piston 15 will rise within the cylindrical body 11, and as a result, the lower slurry space 17 of the cylindrical body 11 will be in a reduced pressure state,
Sludge flows into the lower slurry space 17 from the slurry tank 10 via the pipe 9.

On the other hand, while repelling electromagnets Ml and M3, electromagnet M
2. When M4 is sucked, the piston 15 moves down within the cylindrical body 11, and the slurry present in the lower slurry space 17 is pumped into the green molding space 4 via the pipe 6.

Also shown in FIGS. 2 to 4 is a device for controlling the operation of the pumping device 7 in response to pressure fluctuations within the pipe 6.

In the figure, 20 is a pressure detection sensor arranged concentrically around the pipe 6 which can expand and contract radially in response to fluctuations in the pressure of the slurry; 21 is an excitation current control circuit that sends operating signals to the electromagnets M1 to M4; 22 is a control wiring that connects the pressure detection sensor 20 and the excitation current control circuit 21; 23 is the control wiring 2;
2 is an error amplifier provided above, and 24 is a pressure setting command.

Further, an example of the pressure detection sensor 20 is shown in FIG. 3, where 25 is a sensor flail disposed concentrically around a pipe 6 that can be expanded and contracted radially, and 26 is a sensor flail 26 arranged 180 degrees inside the sensor flail 25. The detecting section 27 mounted at the opposing position is a moving element that moves back and forth within the detecting section 26 by expansion and contraction of the pipe 6 due to pressure fluctuations of the slurry.

Note that FIG. 3 is an enlarged explanatory diagram of the detection unit 26 and the moving element 27, and shows the primary coil 26a and the secondary coil 26b.
, 26c, a voltage is generated by moving the moving element 27 between the excitation current control circuit 2 and the excitation current control circuit 2.
1 can be controlled.

With this configuration, when the pressure of the slurry inside the pipe 6 increases, the pipe 6 expands and its outer diameter increases, and the gap between the sensor flail 25 and the pipe 6 changes, but this change can be detected electrically. Electromagnets M1 to M4 so that the gap is constant
The strength of the slurry can be controlled to keep the pressure of the slurry constant.

[Effect]

Next, a green mold molding operation using the green mold molding apparatus having the above configuration will be explained.

The electromagnets M1 to M4 are driven by the excitation current control circuit 21 to raise and lower the piston 15 within the cylindrical body 11, and suck the slurry from the slurry tank 10 into the lower slurry space 17 of the cylindrical body 11. The slurry is transferred to the lower slurry space 17.
From there, it is fed under pressure to the green molding space 4.

In such a pumping operation, in order to control the slurry pressure, a change in the outer diameter of the pipe 6 is detected, and the detection signal is fed back to the electromagnets M1 to M4 via the excitation current control circuit 21 to control the pressure of the green molding space 4. The slurry pressure can be kept constant.

〔Effect of the invention〕

With the configuration described above, the present invention has the following effects.

■ Constantly detects the pressure of the slurry being pumped into the green molding space,
By controlling the electromagnet by feeding back the detection signal to the pressure feeding device, the slurry pressure at the entrance of the green molding space can be kept constant, and a high-precision green mold can be molded.

■ Since the structure is simple, repairs are easy.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the overall configuration of the green molding device according to the present invention, Fig. 2 is a control circuit diagram, Fig. 3 is an enlarged explanatory diagram of the pressure detection sensor, and Fig. 4 is an enlarged view of the main parts of the pressure detection sensor. An explanatory diagram, FIG. 5, is an explanatory diagram of the overall configuration of a conventional green molding apparatus. In the figure, 1: Formwork 2: Upper mold 3: Lower mold 4: Green molding space 5: Check valve
6: Piping 7: Pressure feeding device 8: Check valve 9: Piping 10: Slurry tank 11: Cylindrical body
12: Upper wall 13: Intermediate wall 14: Lower wall 15: Piston 16: Pasokin 17: Lower slurry space 20: Pressure detection sensor 21: Excitation current control circuit

Claims (1)

[Scope of Claims] 1. A mold having a slurry tank for storing slurry, a slurry pumping device communicating with the slurry tank through a slurry feeding pipe, and a green molding space communicating with the slurry pumping device through a slurry pumping pipe. A green molding device comprising: a slurry pumping device; a cylindrical body having an upper wall and a lower wall;
A piston that is slidably disposed inside the cylindrical body and forms a lower slurry space in the lower part of the cylindrical body, an electromagnet buried in the upper and lower parts of the piston, and an upper wall and a lower part of the cylindrical body. It is embedded in the wall and consists of an electromagnet that attracts and repels the electromagnet in the piston, and a pressure detection sensor that detects the slurry pressure is attached to the slurry pumping piping. A green molding device characterized by being equipped with a control device that controls the magnetic force of an electromagnet.