JPH0195842A - Method and apparatus for fitting sand core in metallic mold - Google Patents

Abstract

PURPOSE:To prevent looseness and coming-out and to surely and easily hold a sand core by fitting a cylindrical member composing of elastic body to out of the projecting part of the sand core, further pushing and compressing the cylindrical member to the projecting part of the sand core respectively toward the metallic mold and fitting. CONSTITUTION:The projecting part 5b formed in the sand core 5 is inserted into fitting hole 1a arranged in the metallic mold 1 and protruded to outside from inside of a cavity 4 and fitted to out of the projected part 5b protruded while expanding the cylindrical member 6 composing of the elastic body. Further, the cylindrical member 6 is pushed and compressed to the projected part 5b relatively toward the metallic mold 1 to hold the sand core 5. In this method, the stress does not locally concentrated and further, at the time of receiving vibration, the vibration can be absorbed by the cylindrical member 6 and the sand core 5 can be surely held.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method and apparatus for holding a sand core in place within a mold cavity.

(Prior Art) When molding a casting using a sand core, the sand core must be accurately mounted at a predetermined position within the mold. Therefore, for boat fishing, a method is used in which the sand core is held by a plurality of positioning city waters. However, when casting using positioning city water, many unnecessary holes are formed in the cast product, so it is necessary to fill the holes, which increases the number of steps.

Therefore, there is a method or a mounting device (
Various types of holders have been proposed.

For example, in the technical report published by Japan Institute of Invention and Innovation, branch number 86-4173 and branch number 86-5225, the protrusion formed on the sand core is made to protrude outside from the cavity of the mold, and the protrusion Disclosed is an apparatus for suspending and installing a sand core within a mold cavity by engaging a retainer with the sand core.

In addition, in Japan Institute of Invention and Innovation, Branch No. 86-4174 and Japanese Patent Application Laid-open No. 60-102248, it is stated that a protrusion formed on a sand core is pressed from the side using the biasing force of a spring. Disclosed is an apparatus for holding and holding an object.

Furthermore, Japanese Utility Model Application No. 60-195142 discloses a device for suspending a sand core in a cavity by using a magnet to attract an iron ring provided on the sand core.
JP-A-60-102250 and JP-A-60-1
In 02251, a concave part is formed in the mold corresponding to the convex part of the sand core, and the inside of the concave part is degassed using a vacuum pump, etc., and the sand core is sucked into the convex concave part of the sand core. A method of suspending the material within the cavity is disclosed.

(Problems to be Solved by the Invention) However, the above-mentioned conventional mounting method or mounting device has the following problems.

First, in the case where the holder is held by engaging with the convex part of the sand core, and in the case where the holder is held by pressing the convex part of the sand core from the side using the urging force of a spring, the engagement Since stress is concentrated at the location and the pressed location, there is a problem in that when vibration or the like is applied, there is a risk that the convex portion of the sand core may be damaged from that location.

Furthermore, these devices and those that use magnets to attract and hold the sand core may become loose or come off from the mold when subjected to vertical vibrations caused by the movement of the mold. There was a problem that there was a risk.

In addition, devices that suck and hold sand cores using a vacuum pump, etc. require equipment such as vacuum pumps, valves, and conduits to be installed, resulting in high equipment costs and the need for a large installation space. There was a point.

The present invention has been made in view of the above problems, and its purpose is to provide a method and device for attaching a sand core that can reliably and easily hold the sand core in a cavity. There is a particular thing.

(Means to solve the problems) The first means to solve the above problems and achieve the purpose.
This will be explained in detail with reference to the drawings and FIG.

First, the sand core is installed by inserting the convex fi5b formed on the sand core 5 into the hole 1a and protruding from the cavity 4 to the outside. A cylindrical member 6 made of an elastic body is expanded and fitted onto the convex portion 5b, and the cylindrical member 6 is compressed by being pressed against the mold 1 relative to the convex portion 5b. This is to hold the sand core 5.

Next, the device includes a convex portion 5b formed on the sand core 5, and a mounting hole formed on the mold 1 through which the convex portion 5b of the sand core 5 can be inserted from inside the cavity 4 to the outside. 1a and
The attachment comprises a cylindrical member 6 made of an elastic material and having a hole 6b having a diameter smaller than the diameter of the convex portion 5b projecting outward from the hole 1a.

(Function) When the sand core 5 is assembled into the cavity 4 by the above method,
Since the convex portion 5b is held by the elastic force of the cylindrical member 6,
Stress is not locally concentrated, and furthermore, when vibration is received, the cylindrical member 6 can absorb the vibration, and the sand core 5 can be held securely.

Furthermore, by compressing the cylindrical member 6 by pressing it against the mold 1 relative to the convex portion 5b of the sand core 5, the repulsive force generated when the compression attempts to return to its original state is It works to pull child 5 upward. Therefore, the cylindrical member 6 and the upper part of the sand core 5 work together to generate a force to clamp the mold 1, so that the sand core 5 is firmly held, and the sand core 5 is held firmly, especially in the sand due to vertical vibration. Loosening and coming off of the child 5 is reliably prevented.

Next, in the above-mentioned device for attaching the sand core 5, the sand core 5 is
To attach the mold 1, the convex portion 5b formed in the mold 1 is inserted into the hole 1a to protrude from the cavity 4 to the outside, and a cylindrical member 6 made of an elastic body is fitted onto the protruded portion.

In this way, by holding the sand core 5 by the cylindrical member 6, stress is not concentrated, and the molds 1, 2, 3
The cylindrical member 6 absorbs the vibrations and can reliably hold the sand core 5 in an accurate position. Note that when fitting the cylindrical member 6 onto the convex portion 5b, the convex portion 5 is
When pressed against mold 1 and compressed relative to b,
A similar effect occurs in that the sand core 5 can be firmly held.

(Example) Next, an example of the present invention will be described based on FIGS. 1 and 2.

1.2.3 is a mold for casting, and by clamping the molds, a cavity 4 is formed inside. Further, the mold 1 is provided with a mounting hole 1a that communicates the cavity 4 with the outside.

5 has a sand core, and the mold l is placed on the upper part of the core part 5a.
The mounting is performed using a conical convex portion 5b having a diameter that can be inserted into the hole 1a,
A columnar pedestal portion 5C is integrally formed.

Reference numeral 6 denotes a cylindrical member for attaching the sand core 5 in a suspended state within the cavity 4. The cylindrical member 6 is made of rubber and has a cylindrical body 6a. Child 5
The convex portion 5b and the through hole 6b into which it is fitted are formed on the axis.

The method and operation of installing a sand core using the apparatus having the above configuration will be explained.

First, to install the mold 1 from inside the cavity 4 of the mold 1, 2.3, the convex portion 5b of the sand core 5 is inserted through the hole 1a, and the pedestal 5c
or protrude outward until it abuts the inside of the mold l.

Next, the convex portion 5b is fitted into the cylindrical member 6 while enlarging the through hole 6b, and the cylindrical member 6 is further pressed against the surface of the mold l relative to the convex portion 5b of the sand core 5. .

In this way, the protrusion 5 is placed in the through hole 6b of the cylindrical member 6.
The convex portion 5b is expanded due to the elastic force caused by the expansion of the diameter when the convex portion 5b is inserted.
will be retained. Furthermore, the cylindrical member 6 is placed in the mold 1.
After being compressed by pressing it against the surface, a force is generated that tries to compress or return in the axial direction. This force acts on the convex portion 5b to pull up the sand core 5, and cooperates with the cylindrical member 6 or the pedestal 5C of the sand core 5 to firmly clamp the mold l.
Thereby, the sand core 5 will be firmly held.

In this way, since the convex part 5b is held by the cylindrical member 6 made of rubber, stress is not intensively applied to the convex part 5b and damage is prevented.
2.3 It absorbs the vibrations generated when opening and closing, etc., and is held firmly against vibrations in the vertical direction, so it reliably prevents loosening or coming off.

Next, the dimensional relationship between the cylindrical member 6 and the convex portion 5b of the sand core 5 for effectively producing the above effect will be explained in detail.

The cylindrical member 6 is made of rubber and has a hardness of H, A45 to 7.
5 (JISA), and the maximum interference with respect to the convex portion 5b of the sand core 5 is 1.0 to 5.5 in diameter. hm, and the ratio of the outer diameter to the inner diameter (outer diameter/inner diameter) is set to be 1.5 or more.

The reason for this setting is that when fitting the cylindrical member 6 into the convex portion 5b of the sand core 5, if the material is made of soft rubber with a hardness of less than HSA 4S, the rigidity will be insufficient and it will not fit easily, resulting in poor workability. This is because the holding force of the convex portion 5b is not sufficient. In addition, if the hardness is H, A75 or higher, the recess 5a
This is because it is necessary to push in with great force when fitting it into the housing, and there is a risk of damaging the four parts 5a at that time.

When using rubber with a hardness in this range, the maximum tightening margin for the protrusion 5b to sufficiently hold the protrusion 5b of the sand core 5 is as follows: Diameter 1. On++s or more is required, hardness H, A
In the case of a soft material such as 45, the diameter is 5.0 mm.
or is necessary.

Regarding the wall thickness of the cylindrical member 6, it has been experimentally determined that the ratio of the outer diameter to the inner diameter (outer diameter/inner diameter) is required to be 1.5 or more within the above hardness range and tightening range. It has been demanded.

Next, a cylindrical member according to another embodiment will be explained using FIGS. 3 and 4.

The cylindrical member 7 shown in FIG. 3 has a plurality of projections 7b extending in the axial direction on the inner circumference of one through hole 7a. With this configuration, the convex portion 5 of the sand core 5
When b is inserted, the frictional force between the through hole 7a and the convex portion 5b increases, so that slipping is further prevented and the holding power of the sand core 5 is improved.

The cylindrical member 8 shown in FIG. 4 has a plurality of annular projections 8b arranged on the inner periphery of one through hole 8a. With this configuration, as with the cylindrical member 7 shown in FIG. or improve.

(Effects of the Invention) As explained in detail above, the mounting method of the present invention includes:
A cylindrical member made of an elastic body is fitted onto the convex part of the sand core, and the cylindrical member is compressed and attached to the mold relative to the convex part, so stress is concentrated on the convex part. This not only eliminates the possibility of the sand core being exposed to the parts, but also allows the sand core to be firmly attached to the mold, and even when subjected to vibrations, the sand core can be securely and easily held without loosening or coming off. Can be done.

Therefore, castings with stable quality can be provided.

Further, the device of the present invention can reliably hold the sand core, has a simple structure, and is easy to install, thereby improving workability and reducing costs.

Furthermore, since it is easy to attach the cylindrical member to the convex portion, it becomes possible to automate the installation of the sand core into the casting mold.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a state in which a sand core is held by a cylindrical member according to an embodiment of the present invention, and FIG. 2 shows the sand core and mold cylinder shown in FIG. 1. An exploded perspective view showing how the cylindrical member is assembled; FIG. 3 shows another embodiment of the cylindrical member;
Figure 3(a) is its side view, Figure 3(b) is its side view, and Figure 3(b) is its side view.
4 shows another embodiment of the cylindrical member, and FIG. 4(a) is a side view of a part thereof, and FIG. 4(b) is a plan view. 1... Mold 1a... Mounting hole 4... Cavity 5... Sand core 5b... Convex part 6... Cylindrical member 6b... Through hole (hole of cylindrical member) ) Patent applicant Toyota Motor Corporation Figure 1 Figure 2 6, 1 Figure 3 (G) (b) Yu /, f! 91 '717' + k! N

Claims (2)

[Claims] (1) The protrusion formed on the sand core is inserted into the mounting hole provided in the mold to protrude from the inside of the cavity to the outside, and then, while expanding the cylindrical member made of an elastic material into the protrusion, A mold characterized in that the sand core is held in the mold by fitting the cylindrical member outwardly and compressing the cylindrical member by pressing it against the mold relative to the convex part. How to install a sand core. (2) a protrusion formed on the sand core; a mounting hole formed on the mold through which the protrusion of the sand core can be inserted from inside the cavity to the outside; and the protrusion protruding from the mounting hole to the outside. A device for attaching a sand core in a mold, comprising: a cylindrical member having a hole smaller in diameter than the diameter of the part and made of an elastic body;