JPH0134700B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold, and particularly to a method for fixing a core to a mold in which the mold is clamped and opened in a horizontal direction.

The core is essential for obtaining hollow castings, and molten metal is poured into the space formed by the mold and the core, the so-called cavity, to obtain castings of a predetermined shape. Therefore, in order to obtain a cavity in the shape of a product casting, the core must be maintained in a predetermined position relative to the mold, so a baseboard is usually formed on the core. Reliable retention of the core is achieved by engaging it with a baseboard support provided in the mold.

However, depending on the shape of the product casting, the baseboard portion may be formed only on one side of the core, as shown in FIG. In such cases, the product after casting is usually removed from the mold in the same direction as the movable mold, so the core is not held securely and can easily be removed by the force of the injected molten metal. This sometimes causes the phenomenon of ``core collapse,'' and a situation occurs in which a product casting of a predetermined shape cannot be obtained due to poor hot water circulation. In addition, in the same figure, 1 is a mold (only the fixed mold is shown in the figure), 1a is an insert provided in the mold 1 as a baseboard holder, 2 is a core, and 2a is a mold attached to the core. The baseboard is formed, and 3 is the cavity.

In addition, when the mold is clamped horizontally as shown in the figure, after the core is positioned in the fixed mold and before the mold is clamped by the movable mold, the movable mold side of the core is in an open state. Since it is,
In order to maintain the positioned core in the same position so that it does not fall over, a separate support means other than the baseboard is required.

The present invention has been made in view of the above, and its purpose is to maintain this positioned state at least until the molten metal solidifies, without relying on additional support means, after positioning the core in the mold. An object of the present invention is to provide a method for fixing a core that can be stably maintained.

That is, the core fixing method according to the present invention involves fixing a sand core in which the baseboard portion is formed only on one side to a mold that is closed and opened in the horizontal direction.
The baseboard part of the sand core with the protruding direction diagonally downward is attached to a baseboard holder provided in the mold body of either the fixed mold or the movable mold with the closed part lower than the opening part. , which is characterized by being inserted and fitted in a direction inclined downward with respect to the horizontal direction.

Embodiments of the present invention will be described below based on the drawings.

FIG. 2 shows an embodiment of the present invention, in which a mold with a core positioned therein is shown in a state before the mold is clamped. Therefore, only one of the molds, the fixed mold, is shown.

In the case of this example, the mold is a thin metal mold that follows the shape of the product as shown in the figure, and a hole made at one side of the mold, that is, slightly above the center of the fixed mold 1, is used as a baseboard holder. Insert 1 made of steel etc.
a is attached, and this insert 1a is in a state of protruding to the back side of the mold surface of the fixed mold 1 (to the left in the figure). The insert 1a has a U-shaped cross section and has a space for receiving the baseboard 2a, and is fixed to the fixed mold 1. The projecting direction of the insert 1a is slightly inclined downward with respect to the horizontal direction indicated by the arrow, that is, the mold clamping direction. The space for inserting the baseboard portion 2a formed in the insert 1a is also located on the opening side (right side in the figure).
It is formed so that the occluded side (left side in the figure) is downward.

On the other hand, the core 2 is a sand baby whose main component is foundry sand, and the baseboard portion 2 is shaped to correspond to the space of the core 1a.
a is formed. That is, this baseboard portion 2a
is also formed on the core 2 slightly downward to the left (undercut state) in the figure.

The insert 1a and the baseboard portion 2a having such a configuration exhibit a fitted state in which the insert 1a and the baseboard portion 2a are downward to the left as shown in the figure when the core 2 is positioned at a predetermined position of the fixed mold 1. Therefore, even in the illustrated state before mold clamping, the core 2 does not fall to the right in the figure. Then, even if molten metal is poured into the cavity formed by mold clamping,
Due to the force of the pouring and the presence of fluidized molten metal after pouring, the core 2 does not shift its position.

In this case, it is sufficient that the inclination angle α of the insertion/fitting direction with respect to the horizontal direction is a little, for example, about 5°, as described above, but there is no problem in making it a larger angle.

In addition, the figure shows that the bottom surface of the core is also inclined with respect to the horizontal direction, but this is to correspond to the direction in which the baseboard part of the core is inserted into and removed from the baseboard holder. If the corresponding surface of the fixed mold 1 is similarly configured to be inclined and abutted, the core can be held more stably.
However, instead of being inclined like this, it may be a horizontal plane as before.

The present invention is not limited to the above embodiments, but includes the following modifications.

In the above embodiment, the baseboard receiver is formed on the fixed mold, but conversely, the baseboard support may be formed on the movable mold, and the core may be positioned and fixed to the movable mold.

In the above embodiment, as the baseboard receiver, a nest made of the same material as the mold, that is, steel, is used, and this nest is attached to the forming hole of the fixed mold. The baseboard support may be formed integrally with the mold.

According to the present invention, since no horizontal positional shift occurs relative to the mold, the cavity of the product shape can be maintained, and as a result, the occurrence of defective product castings can be suppressed as much as possible. On the other hand, it is possible to reduce the thickness of the product casting, and the weight of the product can be reduced.

[Brief explanation of drawings]

FIG. 1 shows a state diagram in a conventional method, and FIG. 2 shows the same state diagram in an embodiment of the present invention. 1... Mold (fixed type), 1a... Baseboard holder, 2
...Nakako, 2a...Baseki.

Claims (1)

[Claims] 1. When fixing a sand core with a baseboard formed only on one side to a mold that is closed and opened horizontally, the baseboard of the sand core with the protruding direction diagonally downward is Inserting and fitting in a direction tilted downward with respect to the horizontal direction into a baseboard support provided in the mold body of either the fixed mold or the movable mold with the closing part lower than the opening part. Features a core fixing method.