JPH0428677Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The disclosed technology belongs to the technical field of the structure of a molding device used in manufacturing metal casting products.

This invention was developed in a core making device by using return pins that were inserted into a predetermined number of holes in one mold body, which was relatively aligned with the other mold body, and which was freely inserted into the other mold body. An extrusion plate is provided which is integrally fixed to the base end of the extrusion pin and is connected to an advance/retraction actuator such as a hydraulic cylinder so that the mold opening stroke is regulated by a stopper provided on the other mold body. In particular, in the baseboard of the other mold body, when one mold body and the other mold body are matched, the extrusion pin of the other mold body The length is formed to slightly protrude from the inner surface of the other mold body from the loose insertion hole, and between the other mold body and the extrusion plate, there is a gap between one mold body and the other mold body when the mold is opened. This invention relates to a core molding device in which a compression spring is interposed to urge the return action on the extrusion plate.

<Prior art> As is well known, many types of metal mechanical devices use cast parts, and some of these seed casting parts are made only with an outer mold, but a considerable number of types of casting parts are hollow. There is also a method of casting using an outer mold and a core through a baseboard, and in this case, there are various problems that need to be solved.

That is, as schematically shown in FIG. 3, in a general core molding apparatus 1, one mold body 2 is molded to the other mold body 3, and core sand (not shown) is blown into the core molding portion 4. After filling, the molds are matched to form a core, and when the mold is opened, one mold body 2 and the other mold body 3 are separated, and then a forward/backward actuator 5 such as a hydraulic cylinder is pressed to extrude the core through an extrusion plate 6. Board 6
Return pins 8, 8 and extrusion pins 9, 9, whose base ends are integrally fixed to and whose tips abut the parting surfaces 7 of one mold body 2 and the other mold body 3, are A core (not shown) is pushed out by sliding the insertion holes 10, 10....

Therefore, in the process of molding one mold body 2 and the other mold body 3 to form core sand,
It is necessary to perform a so-called air bleed operation to eliminate the air interposed between the other mold body 3 and the core sand, but conventionally, the extrusion pins 9, 9... and their insertion holes 1
Air is vented through a minute gap between 0, 10, and so on.

At that time, since the gap is so small that it becomes clogged with molding sand, silicone, etc. due to the wind pressure of the discharged air when air is removed, there is a risk that the sand will become clogged and make it difficult to bleed the air, making it often impossible to bleed the air. There is a problem in that core molding has to be discontinued when the core is worn out.

<Problems to be solved by the invention> To deal with this, as shown in FIG. Insertion holes 10, 10...
The shank portion of each extrusion pin 9 and the tip portion slide into the insertion hole 10 so that the length is slightly inside the inner surface of the other mold body 3, that is, the length is in the retracted position. This prevents sand clogging from occurring due to air removal.

In the conventional mode, as shown in FIG. 3, the extrusion plate 6 is configured to perform a stroke up to the stopper 11 by the return pins 8, 8. , Therefore, the extrusion plate 6 cannot rise beyond the position shown in FIG.
The return action of each ejector pin 9 is not possible due to the length of the inner retracted portion between the tip of each ejector pin 9 and the insertion hole 10, and air is vented in the minute length portion of the other mold body 3. The drawback was that the air could not be prevented from getting clogged with sand.

Therefore, a convex portion is formed on the core (not shown) after the extrusion pin and interferes with the outer mold.
There was a problem that so-called indentation failure occurred.

To deal with this, it is necessary to have a relief part for the pin hole in the outer mold, but although this countermeasure can be adopted for the baseboard part, in the cavity part, pin marks are formed in the casting of the product, resulting in a negative shape. Therefore, due to product reliability concerns, this countermeasure could not be adopted.

Therefore, if the tips of the extrusion pins 9, 9... are designed to be flush with the inner surface of the other mold body 3, there is an advantage that no unevenness is formed on the core as described above, but each extrusion The amount of sand removed during air removal in the gap between the tip of the pin 9 and the insertion hole 10 is insufficient, and silicon etc. tend to adhere and accumulate as scum on the tip of each extrusion pin 9, resulting in However, there was an inconvenience in that the air was not sufficiently vented.

The purpose of this invention is to solve the problems of core manufacturing based on the above-mentioned conventional technology as a technical issue, and to ensure that sand clogging occurs at the tip of the ejector pin at the baseboard part when air is removed. We provide an excellent core molding device that is beneficial to the field of molding technology in the machine manufacturing industry by preventing air bleed and always ensuring smooth air bleed and forming highly reliable core molds as designed. That is.

<Means/effects for solving the problems> In accordance with the above-mentioned purpose, the structure of this invention, which is based on the scope of the above-mentioned utility model registration claims, is to solve the above-mentioned problems by forming a core using a core-making device. When performing this, core sand is blown into the core molding part formed between one mold body and the other mold body, and
When matching the molds, the other mold body is brought close to the one mold body, and at that time, the air in the core molding section is evacuated from the minute gap between the extrusion pin and the insertion hole.
The return pin and the extrusion pin are integrally connected at their base ends to the extrusion plate, and are pushed by a forward/backward actuator against a spring such as a compression spring integrally provided in the other mold body, so that the tip of the return pin moves to one side. The extrusion pin reaches the parting surface of the mold body and the other mold body, and in that state, the tip of the extrusion pin slightly protrudes from the tip of the insertion hole, that is, the inner surface of the other mold body, and the core sand is fired and the core sand is fired. After the child firing is completed, one mold body and the other mold body are opened, the extrusion pin extrudes the core through the extrusion plate as the advance/retraction actuator is pushed forward, and the extrusion plate pushes out the core through the extrusion plate as the advance/retraction actuator retreats. The return pin is separated from the other mold body by a spring such as a compression spring inserted between the two mold bodies, and at this time, the tip of the return pin is separated from the parting surface between one mold body and the other mold body. At the same time, the ejector pins are also pulled out relatively from the other mold body, and therefore, the shank of each ejector pin is of course relatively retreated from the inside of the other mold body into the insertion hole, and therefore, The shank of each ejector pin and the slag of foundry sand and silicone adhering to its tip are cleaned off with a brush, so the sludge between the ejector pin and the insertion hole is removed, and air is removed during the next mold matching. The clogging caused by slag is constantly removed, and not only the baseboard but also the baseboard,
Measures against sand clogging have also been taken in the cavity.
In addition, technical measures have been taken to ensure that the core is always molded as designed, without causing poor insertion, and without the need to provide relief for ejection pin marks on the baseboard of the outer mold.

<Example> Next, an example of this invention will be described below based on FIGS. 1 and 2. Note that the same parts as in FIG. 3 will be explained using the same reference numerals.

Reference numeral 1' denotes a core molding device, which forms the center of the gist of this invention, and a core molding section 4 is located between one mold body 2 on the upper and lower sides of the figure and the other mold body 3 on the upper side. The core sand is blown and filled to form a predetermined core shape, and hydraulic pressure is used as an actuator for advancing and retracting a machine (not shown) provided at the top of the other mold body 3. An extrusion plate 6 is connected to the cylinder 5, and a parting surface 7 when one mold body 2 and the other mold body 3 are matched together.
The base end portions of return pins 8, 8, .

In addition, 10, 10, . It forms a minute air release clearance.

Reference numeral 11 denotes a stopper, which is integrally connected to the upper part of the other mold body 3 and passes through the extrusion plate 6. The stopper 11 is externally connected between the extrusion plate 6 and the upper surface of the other mold body 3. A compression spring 12 is interposed therebetween.

As shown in the figure, in the baseboard portion of the other mold body 3, one mold body 2 and the other mold body 3 were molded together so that the tips of each extrusion pin 9' were aligned as shown in FIG. At this point, the tip slightly protrudes into the core molding part 4 from the inner surface of the other mold body 3, for example, by about 0.5 mm due to the design, and the slag 13 of silicone etc. that adheres to the tip is shown in Fig. 2. As shown in the figure, when the hydraulic cylinder 5 is raised, the tip of each extrusion pin 9' is drawn into the insertion hole 10, 10, . It is made to be.

In the above-mentioned configuration, core sand (not shown) is blown into the core forming portion 4 of one mold body 2 and the other mold body 3, and the one mold body 2 and the other mold body 3 are brought relatively close to each other to form a core. Perform molding.

At that time, the extrusion plate 6 is pushed forward against the other mold body 3 by the hydraulic cylinder 5 against the compression spring 12, and each return pin 8 is connected to one mold body 2 and the other mold body 3. The tip reaches the parting surface 7 of the pin and stops, and in this state, each ejector pin 9'
As mentioned above, the tip of is inserted into the core molding part 4 from the inner surface of the other mold body 3 in the baseboard part shown in FIG.
Because they protrude slightly, such as by 0.5 mm, the air inside the core molding section 4 in the above process is absorbed by each extrusion pin 9'.
Air is released from a minute gap between the insertion hole 10 and the insertion hole 10.

Then, in this state, the firing process begins, and after firing, the mold is opened and one mold body 2 and the other mold body 3 are separated, but at that time, the hydraulic cylinder 5 rises and the compression springs 12, 12 are released. Due to the elastic force, the extrusion plate 6 rises to the stoppers 11, 11, and each return pin 8 and extrusion pin 9' integrally provided on the extrusion plate retreats within each hole 10 with respect to the other mold body, and As a result, the tip of each extrusion pin 9' is also drawn down into the hole 13 from the inner surface of the other mold body 3, and the slag 13 of foundry sand, silicon, etc. is deposited on the tip of each extrusion pin 9' and the shank. Even if it sticks to the core, it is completely removed by brushing, and there is no need to support the air removal during the next core sand filling or correction, and therefore, there is no possibility of poor pushing due to sand clogging.

Therefore, in this invention, there is no need for relief after the extrusion pin in the outer mold, and since the rear of the extrusion pin does not become convex in the core, flushing can be achieved in the cavity part.

By further applying the pressing force of the hydraulic cylinder 5 when opening the mold, each extrusion pin 9' projects into the core molding section 4, and after extruding a molding core (not shown), the hydraulic cylinder is switched. The hydraulic cylinder 5 rises, and the extrusion plate 6 retreats relative to the other mold body 3 due to the elastic force of the compression springs 12, 12.

It goes without saying that the embodiment of this invention is not limited to the above-mentioned embodiment, and various embodiments can be adopted.

<Effect of the invention> As described above, according to this invention, when one mold body and the other mold body are brought together in the core making device, the inner surface of the other mold body is By firing the tip of each extrusion pin slightly protruding from its insertion hole, air bleed in the core molding part during mold matching can be done in the same way as in the past, by allowing the tip of each extrusion pin to protrude slightly from its insertion hole. In the process that is carried out through a gap, and after firing the core is pushed out by pressing the advancing/retracting actuator, even if the advancing/retracting actuator retreats, the extrusion plate retreats to the stopper provided on the other mold body 3 by the compression spring. It has the excellent effect of cleaning not only the shank part but also the slag of silicone, etc. that has adhered to the tip part, preventing the sand from passing through the next time, and preventing sand clogging defects. It is played.

Moreover, since each extrusion pin protrudes slightly from the inner surface of the other mold body 3 in the mold assembly itself,
The convex shape of the core is not formed not only in the baseboard part but also in the cavity part, so there is no indentation defect in the outer mold, there is no need to release ejector pin marks, and the surface of the cavity part is not formed. An excellent effect can be achieved in that unification can also be achieved.

In this way, the process in the core molding process is always stable, reducing sand clogging defects in the core, and eliminating the need to provide relief for ejector pin marks on the outer mold baseboard, which also causes poor insertion. In addition, there is no need to take measures against sand clogging caused by the ejector pin in the cavity, which is an excellent effect.

Therefore, there are many effects such as increased reliability in product accuracy and improved durability of the core molding device.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of one embodiment of this invention. Figure 1 is a sectional view of air removal during mold matching, Figure 2 is a sectional view of removing slag from each extrusion pin, and Figure 3 is a conventional FIG. 3 is a cross-sectional view of the core molding device based on the technology during mold matching. 2...One mold body, 3...The other mold body, 1
0,10'...Insertion hole, 8...Return pin, 9
. . . Extrusion pin, 11 . . . Stopper, 5 .

Claims (1)

[Scope of utility model registration request] A return pin and an extrusion pin are loosely inserted into a hole in the other mold body, and the stroke is regulated by a stopper provided in the other mold body. In a core molding device having an extrusion plate,
The extrusion pin of the baseboard of the other mold body is formed to a length that slightly protrudes from the inner surface of the other mold body when the molds are matched, and a compression spring is interposed between the other mold body and the extrusion plate. A core molding device characterized by: