JPS6351784B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The disclosed technology belongs to the field of technology in which a cavity formed in a mold is filled with core sand and fired to produce a hollow core.

Therefore, this invention forms a core forming cavity in a predetermined core manufacturing mold, fills the cavity with core sand from a core sand filling/discharging port, and heats it to a predetermined temperature. , an invention relating to a core manufacturing method in which core sand is fired to a predetermined thickness in the cavity, and then the mold is reversed or unfired sand is discharged from a filling and discharge port by applying vibration, In particular, when filling the core with sand, gas such as air is injected at low pressure from a pore that is opposite to the filling side and also communicates with the cavity to prevent clogging of the pore. This invention relates to a method for manufacturing a hollow core, in which when unfired sand is discharged in a posture, gas is injected from the pores under high pressure to ensure that unfired sand is discharged from all parts.

<Prior Art> As is well known, cast products are widely used for various industrial products, and among these, blow molded products are molded using a casting mold having a core.

Therefore, in casting with a core, it is necessary to mold the core before casting, but it is usually necessary to reduce the weight of the core, reduce the amount of core sand used as a material, and improve the sand removal property after casting. In order to improve the quality of sand, a so-called hollow core is formed, and when molding the hollow core, a core molding device having a reversing sand discharge mechanism is generally used, and a core molding device is used that has a sand discharge mechanism at the top of an upright mold. The core sand of the material is filled into the cavity, the mold is heated to a predetermined temperature, the filled core sand is fired, and after firing for a predetermined period of time, the mold is overturned to form the fired sand inside the cavity. Utilizing the non-caking state of the unfired sand, a hollow core is formed by applying gravity or vibration to gravity and dropping and discharging it, and then the mold is opened and the formed hollow core is formed. I was trying to get it.

<Problem to be solved by the invention> There are cases where the hollow core has a straight tube shape, but there are also cases where the hollow core has a complicated curved shape, and the latter type is required more often. .

In such cases, gravity sand removal by overturning the mold or vibration sand removal means has the disadvantage that it is impossible to completely remove the unfired sand from the complicated narrow areas inside the fired sand.

For this reason, there is a problem that the yield rate of the material core sand is poor, and as a result, there is also the disadvantage of increasing costs.
Another problem was that the core sand did not easily crumble when sand was removed after casting.

<Object of the Invention> In view of the problems of hollow core molding based on the above-mentioned prior art, the purpose of the present invention is to provide a machine that can more reliably discharge the unfired sand in the cavity for hollow core molding. It is an object of the present invention to provide an excellent method for manufacturing hollow cores that will benefit the field of application of casting technology in the manufacturing industry.

<Means and operations for solving the problems> In order to solve the above-mentioned problems, the structure of the present invention, which is based on the above-mentioned claims, is based on a cavity for forming a hollow core in a mold. In the process of filling the material core sand into the cavity, low pressure gas is injected from the pores connected to the cavity on the opposite side from the charging/discharging port to prevent clogging of the pores while filling the material core sand. The charging and discharging ports are filled and the mold is heated to perform firing, and then the mold is turned over and the unfired sand inside the fired sand is discharged by gravity and, if necessary, vibration, and high-pressure gas is pumped through the pores. A technical measure was taken to forcibly discharge the unfired sand by injecting it to obtain a healthy hollow core.

<Embodiment> Next, one embodiment of the present invention will be described with reference to the drawings.

Reference numeral 1 denotes a hollow core molding die, which consists of a fixed mold 1' and a movable mold 1'' on its side, and a cavity 3 for molding the hollow core 2 is as shown in FIG. 3 in this embodiment. It is formed into an L-shape, one end of which is opened in the side surface of the mold 1 to form a charging and discharging port 4 for the core sand, and the other end 5 is formed inside the mold 1, and the other end is A cap 6 made of heat-resistant ceramic is attached to the end via a guide hole 7, and the guide hole 7 has a nipple 8.

As shown in FIGS. 2a and 2b, the cap 6 has rows of slit-type pores 11, 11 in the side surface 9 and the bottom 10 that communicate with the guide hole 7.
A plurality of . . . are provided, and are formed in a size that allows gas to be conducted into the cavity 3, but does not allow the core sand 12, which is the material, to pass through.

Further, 13 is a 4-way 3-position valve for control, and a compressed air source 14 as a gas source and piping 1.
5, and connect the low pressure side pressure reducing valve 17 and the high pressure side pressure reducing valve 1 via check valves 16 and 16'.
It is branched and connected to 7'.

Incidentally, as shown in FIGS. 3 and 4, rotating shafts 18 and 18 are provided on both sides of the mold 1 so as not to hinder the opening of the mold, and are linked to an appropriate rotating mechanism.

In the hollow core molding die 1 having such a structure, 4
Move the direction 3 position valve 13 to the left side in the figure to switch it, and feed compressed air from the gas source, that is, the compressed air source 14, to the low-pressure side pressure reducing valve 17, and set it at a predetermined low pressure to the nipple through the piping 15. 8. Fill the core sand 12 of the raw material through the charging/discharging port 4 of the mold 1 in an upright position by injecting it into the cavity 3 through the pores 11, 11, . . . of the cap 6 through the guide hole 7.

Therefore, the low pressure air injected from the pores 11, 11... does not prevent or disturb the filling of the core sand 12 into the cavity 3, but the low pressure air injected from the pores 11, 11... Clogging of child sand is prevented from occurring.

After filling the cavity 3 with the sand core 12 of the raw material, the mold 1 is heated to a predetermined value and the filled core sand 12 is fired, as in the conventional method, and the core sand is 12, a core 2 is formed from the inner surface of the cavity 3 to a set thickness of several millimeters by firing the manufacturing components.

When the core 2 of a predetermined thickness is formed, the mold 1 is rotated 180 degrees through the rotation shafts 18, 18 by the rotating mechanism to an inverted position, and the unfired sand 1 inside the core 2 is blown by its own weight. ' falls from the charging/discharging port 4 and is discharged, and as the case may be, appropriate vibrations are applied to energize and discharge the battery.

However, it is difficult to completely and quickly discharge the unfired sand 12' due to gravity or vibration force in the case of the embodiment having bottlenecks, bends, etc. Directional position valve 1
3 to the right side in the figure, the pressure reducing valve 17' is switched to the high pressure side, and compressed air at a set high pressure is injected from the pores 11, 11... of the cap 6, and the unfired core sand 12 is forced by the jet dynamic pressure. ' is discharged from the charging/discharging port 4.

After all of the unfired sand 12 has been discharged in this manner, the molds 1' and 1'' are opened to obtain the core 2 during molding.

It goes without saying that the embodiments of this invention are not limited to the above-mentioned embodiments; for example, various embodiments such as a complex embodiment in which the cavity has a further curved bottleneck, and one in which the pores are in the form of spot perforations are possible. can be adopted.

<Effects of the Invention> As described above, according to the present invention, after the cavity in the mold is filled with the core sand of the material and fired, the unfired sand is discharged while the mold is in an upright state. By injecting low-pressure gas from the pores in the cavity communication section on the opposite side of the charging/discharging port during filling, the core sand does not clog the pores and prevents the core sand from passing through the gas in the subsequent stage. This has the effect of not interfering with the pressurized discharge of fired sand.

Therefore, when the mold is inverted and the unfired sand is discharged and dropped by applying its own weight or vibration to the dead weight from the lower charging/discharging port, high-pressure gas is injected from the pores. As a result, the high-pressure gas can forcefully discharge the unfired sand, and therefore, even if the cavity, i.e., the firing core, has a crooked hollow part such as a bottleneck or a narrow part, the sand can be reliably removed. This has the excellent effect of allowing unburned sand to be discharged.

As a result, the amount of core sand used is close to the designed amount, which improves yield and has the advantage of reducing costs.

In addition, since the hollow core is made uniform to the designed thickness, a sound core can be obtained, and there is also an advantage in post-processing that no block-like sand lumps are formed during demolding.

[Brief explanation of the drawing]

The drawings show one embodiment of the invention,
Figure 1 is a cross-sectional view of the mold, Figures 2a and 2b are the side and front views of the cap, Figure 3 is a partial cross-sectional view of the sand filling of the raw material core, and Figure 4 is the part where unfired sand is discharged. The sectional view, FIG. 5, is a mechanical diagram of the control valve. 1, 1', 1''...Mold, 3...Cavity, 12...
Core sand, 4...charging/discharging port, 2...burning sand (hollow core),
12'...unfired sand, 11...pores.

Claims (1)

[Claims] 1 After filling the cavity formed in the mold with core sand from the charging and discharging ports, it is fired for a predetermined period of time to form a core of a predetermined thickness in the cavity with the fired sand, and then the mold is turned over. In the method for producing a hollow core, in which unfired sand is discharged from the charging and discharging port, when filling the raw material core sand, the pressure is lower than that of the pore communicating with the cavity on the opposite side from the charging and discharging port. A hollow core characterized in that clogging is prevented by injecting gas, and when the unfired sand is discharged, high pressure gas is injected from the pores to discharge all the unfired sand. Production method.