JPH06238395A - Device for holding sand core - Google Patents

Abstract

PURPOSE:To provide a sand core holding device capable of adjusting the sand core holding force in a die. CONSTITUTION:A core print part 3a in the sand core 3 is positioned in a fixing die 2. A holding pin 4 is shiftably arranged in a working hole 5 in the fixing die 1 and is arranged in approachable/separable to and from the core print part 3a by cylinder mechanism 6. The cylinder mechanism is driven with the air pressure by cylinder driving mechanim 10 and the driving mechanism 10 is controlled through a control part 20. At the tip part of the holding pin, a projecting part 4a and a flat surface part 4b are arranged. The projecting part 4a can cut into the core print part 3a and the flat surface part 4b abuts on the surface of the core print part after the projecting part cuts into the part 3, and further shifting of the holding pin is prevented. By this method, the holding force is adjustable according to the strength of the sand core, and breakage, crack and slippage of the sand core are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sand core holding device,
Particularly, the present invention relates to a sand core holding device capable of adjusting the holding force of the sand core.

[0002]

2. Description of the Related Art In order to cast a product having a hollow portion, a method of fixing a sand core in a mold cavity and filling it with a molten metal has been conventionally performed. In order to hold the sand core in a predetermined position in the mold, a method of providing a convex portion on the sand core and inserting it into the concave portion of the mold, and conversely a method of fitting the core concave portion to the convex portion of the mold Has been proposed in the past. Also, JP-A-60-1022
In the invention described in Japanese Patent Publication No. 48, the skirting board of the sand core is positioned so as to project into the mold, and the pin is movably provided in the hole formed in the mold and communicating with the skirting board. A spring is provided as an urging means on one end side of the holding pin in the mold to urge the pin in the direction of the skirting board, and the other end surface of the pin presses the skirting board to remove the sand core. Techniques for maintaining position within a mold have been disclosed.

[0003]

However, in the above-described conventional concave-convex fitting method, an opening which is unnecessary in terms of performance is formed in the cast product, and the work of filling this opening is required. Therefore, workability is deteriorated and the product strength is lowered at the opening. Further, in the invention described in JP-A-60-102248, since the spring is used as the urging means, it is not possible to easily change the holding strength according to the strength of the sand core, and it is necessary to adjust the strength. If the holding strength is too high, the sand core may be damaged, and if it is too low, the sand core may fall off. Furthermore, the spring may deteriorate due to heat, making it difficult to maintain its holding strength.
Since the holding pin always projects from the mold surface, the sand core surface may be damaged when the sand core is inserted, and the sand may drop off.

Therefore, the present invention overcomes the above-mentioned problems of the prior art, and, in order to prevent the sand core from falling off or moving, when the sand core is held at a predetermined position in the mold, the sand core is not damaged. An object of the present invention is to provide a sand core holding device capable of adjusting the sand core holding force and providing reliable holding.

[0005]

In order to achieve the above object, the present invention provides a sand core holding device for holding a sand core having a skirting board in a mold, comprising: (a) the skirting board. A protrusion formed to be able to bite into the inner surface of the mold, and a flat portion that abuts on the skirting portion and follows the protrusion to stop the biting operation of the protrusion. A holding pin that holds the sand core by an action, and (b) a cylinder mechanism that is connected to the holding pin and that moves the holding pin forward and backward to move the holding pin away from and approach the skirting board.
There is provided a sand core holding device including (c) a cylinder drive mechanism connected to the cylinder mechanism for driving the cylinder mechanism, and (d) a control unit for controlling the cylinder drive mechanism.

[0006]

According to the sand core holding device of the present invention having the above structure, when the cylinder drive mechanism drives the cylinder mechanism by the signal from the control unit, the holding pin which is connected to the cylinder mechanism and which is initially in the retracted position is in the sand. Move toward the skirting part of the child. The protrusion of the holding pin bites into the skirting board, and the flat portion comes into contact with the surface of the skirting board to prevent movement of the holding pin, and the sand core is set at a desired position in the mold.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a sand core holding device according to the present invention will be described with reference to FIGS. The sand core 3 shown in FIG. 1 is for forming a hollow portion corresponding to a water jacket portion of a closed type cylinder block, for example.

A fixed die 1 is provided with a fixed die 2,
A cavity (not shown) is defined between the cavity and a movable die (not shown). The sand core 3 is provided with a skirting board portion 3a, and the skirting board 3a is positioned in contact with the inner wall surface of the fixed die. The sand pin is held at a predetermined position in the mold cavity by pressing the skirting board portion 3a by the holding pin 4. A holding pin operating hole 5 is linearly formed in the fixed mold 1 and the fixed die 2, and one end of the operating hole 5 is open to the cavity. The holding pin 4 is movably provided in the operation hole 5.

One end of the holding pin 4 has a flat surface 4b,
Further, the protrusion 4a is provided so as to be able to bite into the skirting portion 3a. The other end of the holding pin 4 is integrally provided with a screw portion 4c for connecting to a cylinder mechanism 6 described later. The protrusion 4a of the holding pin 4 can bite into the skirting part 3a, but further biting is prevented by the contact between the flat surface 4b and the surface of the skirting part 3a. The flat surface portion 4b functions as a stopper when the protruding portion 4a bites.

A cylinder mechanism 6 is provided to allow the holding pin 4 to move within the holding pin operating hole 5. The cylinder mechanism 6 has a cylinder 6a, a piston 6c capable of reciprocating in the cylinder 6a, and a piston rod 6b provided integrally with the piston 6c, and the screw portion 4c is provided at the end of the piston rod 6b. It is screwed. Therefore piston 6
By the reciprocating movement of c, the holding pin 4 can be moved toward and away from the skirting board portion 3a. The cylinder 6a is the piston 6c
To define a first chamber 6A and a second chamber 6B.
A and a second chamber 6B are provided with a first port 6d and a second port 6e, respectively.

A cylinder drive mechanism 10 is provided for reciprocating the piston. Cylinder drive mechanism 10
Is composed of a solenoid valve 7 fluidly connected to the first port 6d and the second port 6e, a regulator 8 connected to the solenoid valve 7, and an air source 9 as a pressure fluid source. Solenoid valve 7 is solenoid 7a
Is provided so as to be switchable between the first switching position 7X and the second switching position 7Y, and the air pressure from the air source 9 can be changed to the first chamber 6
It is configured to be introduced into either A or the second chamber 6B. That is, the solenoid valve 7 moves to the first switching position 7X.
When in (FIG. 1), the air source 9 is connected to the first chamber 6A through the first port 6d, and the second chamber 6B is connected to the atmosphere through the second port 6e and the solenoid valve 7. . On the other hand, when the solenoid valve 7 is in the second switching position 7Y, the air source 9 is connected to the second chamber 6 via the second port 6e.
Further, the first chamber 6A is connected to the atmosphere via the first port 6d and the solenoid valve 7. The regulator 8 is provided to adjust the air pressure of the air source 9. The air pressure is set by the strength of the sand core 3 and the diameter of the holding pin 4.

A control unit 20 for controlling the cylinder drive mechanism 10 is further provided. The control unit 20 includes an electric circuit 11, a switch 12, and a casting machine timer 13. The control unit 20 is provided to generate a switching signal for the solenoid valve 7, and is connected to the solenoid 7a. The switch 12 is connected to the electric circuit 11,
It is provided to generate a positioning signal for the solenoid valve 7 to start the pressing operation of the skirting portion 3a by the holding pin 4. The casting machine timer 13 is also connected to the electric circuit 11 to define the sand core holding time of the holding pin 4.

3 to 9 are examples showing various shapes of the protrusion 4a of the holding pin 4. As shown in FIG. The projection 4a has a cone shape (FIG. 3), a pyramid shape (FIG. 4), a wedge shape (FIG. 5), a truncated cone shape (FIG. 6) having a biting and suspending force with respect to the sand core skirting board portion 3a. Pyramidal trapezoid (Fig. 7), Asymmetric taper (Fig. 8)
The protrusion 4a may be a single protrusion, or a plurality of these may be arranged for the purpose of stopping the rotation of the sand core 3 (FIG. 9). When providing a plurality of protrusions 4a, a plurality of protrusions 4a may be provided in the same or different shape. It is preferable that the projection shape and the flat area ratio of the holding pin 4 are selectively determined by the strength of the sand core 3, and the height of the projection 4a at the tip of the holding pin 4 is the projection shape and the sand content. Determined by strength of child 3. Therefore, it is advisable to prepare various holding pins 4.

Next, the operation of the sand core holding device according to the above embodiment will be described. Before the operation is started, the movable mold (not shown) is in a mold open state separated from the fixed mold 1, and the solenoid valve 7 is also in the second switching position 7Y. First, sand core 3
The skirting board portion 3a is positioned on the fixed die 2. Next, when the switch 12 is turned on by a manual operation, a positioning signal is output to the electric circuit 11. A switching signal is output from the electric circuit 11 in response to the positioning signal, and the solenoid valve 7 is switched to the first position 7X. Therefore, the compressed air of the air source 7 flows into the first chamber 6A of the cylinder 6 through the first port 6d while being regulated by the regulator 8, and the holding pin 4 is held through the piston 6c and the piston rod 6b. It slides in the operating hole 5 and moves in the direction of the skirting board 3a. On the other hand, the air in the second chamber 6B is discharged to the atmosphere through the second port 6e and the solenoid valve 7.

As a result, the protrusion 4a of the holding pin 4 bites into the skirting board 3a of the sand core 3, and when the flat surface portion 4b of the holding pin 4 abuts the surface of the skirting board 3a, the holding pin 4 is further updated. Is prevented from moving.

Next, the movable mold (not shown) is moved toward the fixed mold 1 to perform mold clamping, and the space inside the cavity defined by the sand core 3 and the movable die (not shown) is filled with the molten metal. It Cooling is performed for a predetermined period, and after the time specified by the casting machine timer 13, the solenoid valve 7 is moved to the second switching position 7Y.
Is switched to. Then, the compressed air of the air source 7 flows into the second chamber 6B of the cylinder 6, while the air in the first chamber 6A is discharged to the atmosphere via the first port 6d and the solenoid valve 7, so that the holding pin Reference numeral 4 slides in the holding pin operating hole 5 and moves in a direction away from the skirting board portion 3a. Therefore, the sand core 3 is released from being held by the holding pin 4. Next, the mold is opened, the cast product is extruded by an extruding pin (not shown) and separated from the movable mold, and the cast product is taken out.

The present invention is not limited to the above embodiments, and various modifications and improvements can be made within the scope of the technical matters described in the claims. For example, a plurality of holding pins 4 may be provided. Further, in order to adjust the pressing force of the holding pin 4, in addition to the adjustment of the fluid pressure by the regulator 8, the adjustment can be performed by changing the diameter of the cylinder 6a and the piston 6c to change the pressure receiving area. Further, it is possible to provide the holding pin 4 on the movable mold side. In this case, the holding pin 4 may be separated from the skirting board 3a after the mold is opened and before the cast product is taken out. Further, hydraulic pressure or hydraulic pressure can be used for the cylinder drive mechanism 10, and in this case, a hydraulic cylinder or hydraulic cylinder is used for the cylinder mechanism 6.

[0018]

According to the sand core holding device of the present invention described above, since the sand core holding force can be adjusted according to the strength of the sand core, the sand core is damaged, cracked, or misaligned. It is possible to prevent falling. Further, since the holding pin can be moved back and forth arbitrarily, the holding pin is retracted at the time of inserting the sand core, so that the sand core is not damaged and the sand does not fall off when the sand core is inserted.

Further, by making the tip of the holding pin bite into the sand core, the movement of the sand core in the direction perpendicular to the presser (the mold moving direction at the time of mold clamping) can be prevented.

In addition, since the pressure fluid is used to move the holding pin, the holding strength can be easily changed in a short time, and once the sand core is held, the holding force is changed. A stable holding force can be maintained without changing.

Further, since the sand core itself does not need to be provided with convexo-concave portions, unnecessary openings are eliminated in the cast product, and workability is improved without the work of finishing holes and filling the openings.
Castings with excellent strength can be made.

[Brief description of drawings]

FIG. 1 is a schematic view showing one embodiment of a sand core holding device of the present invention.

FIG. 2 is a partial cross-sectional view showing a state where a holding pin according to the embodiment holds a sand core skirting portion.

FIG. 3A is a side view showing a first example of the protrusion of the holding pin according to the embodiment, and FIG. 3B is a bottom view thereof.

FIG. 4A is a side view showing a second example of the protruding portion of the holding pin according to the embodiment, and FIG. 4B is a bottom view thereof.

FIG. 5A is a side view showing a third example of the protrusion of the holding pin according to the embodiment, and FIG. 5B is a bottom view thereof.

FIG. 6A is a side view showing a fourth example of the protruding portion of the holding pin according to the embodiment, and FIG. 6B is a bottom view thereof.

FIG. 7A is a side view showing a fifth example of the protrusion of the holding pin according to this embodiment, and FIG. 7B is a bottom view thereof.

FIG. 8A is a side view showing a sixth example of the protrusion of the holding pin according to the embodiment, and FIG. 8B is a bottom view thereof.

9A is a side view showing a seventh example of the protrusion of the holding pin according to the embodiment, and FIG. 9B is a bottom view thereof.

[Explanation of symbols]

 1 Fixed mold 2 Fixed die 3 Sand core 3a Baseboard part 4 Holding pin 4a Projection part 4b Flat part 6 Cylinder mechanism 10 Cylinder drive mechanism 20 Control part

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[Procedure amendment]

[Submission date] February 9, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Next, the operation of the sand core holding device according to the above embodiment will be described. Before the operation is started, the movable mold (not shown) is in a mold open state separated from the fixed mold 1, and the solenoid valve 7 is also in the second switching position 7Y (solenoid valve).
(Lube 7 is on). First, the skirting part 3a of the sand core 3 is positioned on the fixed die 2. Next, when the switch 12 is turned on by a manual operation, a positioning signal is output to the electric circuit 11. In response to the positioning signal, a switching signal (solenoid
OFF signal of the valve 7) is output from the electric circuit 11,
The solenoid valve 7 is turned off and the spring force of the spring 7b causes
The solenoid valve 7 is switched to the first position 7X.
It Therefore, while the compressed air of the air source 9 is regulated by the regulator 8, the compressed air of the air source 9 is transferred to the cylinder 6 via the first port 6d.
Flows into the first chamber 6A, and the holding pin 4 slides in the holding pin operating hole 5 via the piston 6c and the piston rod 6b and moves in the direction of the skirting board portion 3a. On the other hand, the air in the second chamber 6B is discharged to the atmosphere through the second port 6e and the solenoid valve 7.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

Next, the movable mold (not shown) is moved toward the fixed mold 1 to perform mold clamping, and the space inside the cavity defined by the sand core 3 and the movable die (not shown) is filled with the molten metal. It Cooling is performed for a predetermined time, and after a time specified by the casting machine timer 13, the solenoid valve 7 is set to the second switching position 7Y.
Is switched to. Then, the compressed air from the air source 7 flows into the second chamber 6B of the cylinder 6, while the air in the first chamber 6A is discharged to the atmosphere via the first port 6d and the solenoid valve 7, so that the holding pin Reference numeral 4 slides in the holding pin operating hole 5 and moves in a direction away from the skirting board portion 3a. Therefore, the sand core 3 is released from being held by the holding pin 4. Next, the mold is opened, the cast product is extruded by an extruding pin (not shown) and separated from the movable mold, and the cast product is taken out.

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure Amendment 5]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 7

[Correction method] Change

[Correction content]

[Figure 7]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hirotake Usui Ryobi Co., Ltd. 762, Mesaki-cho, Fuchu-shi, Hiroshima

Claims (1)

[Claims] 1. A sand core holding device for holding a sand core having a skirting board in a mold, wherein a projection formed so as to be able to bite into the skirting board and abutting on the skirting board. A holding pin for holding the sand core in cooperation with the inner surface of the mold, and a holding pin for connecting the holding pin, A cylinder mechanism for moving the holding pin forward and backward to move the holding pin toward and away from the skirting board; a cylinder drive mechanism connected to the cylinder mechanism for driving the cylinder mechanism; A sand core holding device comprising: a control unit that controls a mechanism.