JP3182121B2 - Vibration method of foundry sand - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration method for compacting molding sand for casting, and more particularly to a method for vibrating molding sand in which a vibration trajectory of a synthetic vibration applied to the molding sand has a desired Lissajous figure.

[0002]

2. Description of the Related Art In casting using molding sand, compacting and agglomerating molding sand in which a mold is buried is very effective from the viewpoint of improving the shape accuracy, surface roughness, etc. of a molding product to be molded. It is performed in order to form a good casting product.

In the vanishing model casting using the vanishing model, since the mold model is buried in the molding sand, the molding sand containing the molding sand is vibrated from the outside to give the casting sand. Was compacted.

As a vibrating device that vibrates the foundry sand from the outside as described above, conventionally, a piston mechanism that operates horizontally or vertically is installed on a diaphragm, and these piston mechanisms are operated to be fixed to the diaphragm. Micro-vibration is applied to the foundry sand in the mold frame to eliminate the gaps between the foundry sands and agglomerate them, and the foundry sand is firmly adhered to the surface of the mold model.

[0005]

However, the vibration generated by the conventional vibration device is a vibration that reciprocates on a fixed straight line, and the molding sand to which the vibration is applied only moves in the applied vibration direction. is there. For example, when vibration is applied in the X-axis direction, the foundry sand moves only in a direction parallel to the X-axis due to vibration, and hardly moves in other directions. Therefore, if the mold model is open in the X-axis direction, the molding sand is packed inside by applying vibration in the X-axis direction. For example, if the mold model is open in a direction other than the X-axis, There was no casting sand and the casting sand was not sufficiently packed. Furthermore, since the vibrations are even in the left and right directions with the center point of the vibrations as the center, they always vibrate only at a fixed position, and the molding sand cannot flow in a desired direction.

Further, in order to vibrate the molding sand in a plurality of directions on a vibrating table having a constant vibration direction, the mounting direction of the mold frame may be changed. However, when the weight of the flask is from several tons to several tens of tons, it is not easy to move the flask, and the operation becomes large, and the mounting direction of such a heavy flask is changed. Therefore, it was difficult to change the direction of the vibration.

[0007] In addition, the vibration applied in the horizontal direction only moves the molding sand that has been vibrated into the gap formed between the molding sands, and the molding sand drops into the gap by gravity. The molding sand was not compacted due to the force being applied positively in the vertical direction. Therefore, the molding sand could not be solidified in the vertical direction as if pressed from above.

Further, there are examples of a vibration device having a piston cylinder mechanism for moving in a horizontal direction and a vibration mechanism for generating vibration in an up and down direction, and a mechanism for normally giving vibration in a horizontal direction and a mechanism for giving vibration in a vertical direction. Since it is operated separately, it must be vibrated twice, and it is not possible to solidify the molding sand in the vertical direction while moving the molding sand in the horizontal direction. When tightened, there was a gap at the top.

As described above, in the vibration device that applies vibration in the horizontal direction, the direction in which the molding sand moves due to the vibration of the vibration device is horizontal, and is limited to the direction in which the vibration device vibrates. Move molding sand out of the vibration direction of the vibration device,
In particular, in order to compact the foundry sand in the vertical direction, it was necessary to change the mounting position of the flask again or to apply vibration instead of the vibrating table that vibrates vertically.

An object of the present invention is to provide a molding sand vibration method for facilitating the work of compacting molding sand and securely bringing the molding sand into close contact with the mold surface.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention has a method for vibrating molding sand as follows. That is, the reciprocating vibration vibrating in the horizontal direction and the reciprocating vibration vibrating in the vertical direction are combined in synchronism with each other, and the trajectory of the combined vibration forms a predetermined figure, for example, a certain Lissajous figure.

This vibration is the vibration obtained by adding the reciprocating vibration in the Z-axis direction to the reciprocating vibration set in an arbitrary direction in the XY plane. The trajectory of the synthesized vibration forms a predetermined shape.

As specific conditions for vibration, the maximum value of acceleration is 4 m / s (square) to 30 m / s (square), the frequency is 25 to 100 Hz, and the half amplitude is 0.01 mm to
A value of 1.5 times the average diameter of the sand is preferable. In the Lissajous figure formed by the vibration waveform, the inclination Θ (theta) of the axis of the Lissajous figure is from 15 degrees to 75 degrees with respect to the XY plane.
Degree, and the width W with respect to the length L is 0.5 or less,
Further, the waveform of the acceleration of the vibration to be applied was a rectangular wave or a sawtooth wave having one side of the waveform set upright as shown in FIGS.

If the acceleration is less than 4 m / s (square), the foundry sand does not move sufficiently. If the acceleration exceeds 30 m / s (square), the molding sand bounces and does not solidify. By setting the value of the acceleration to the above-mentioned waveform, shocking vibration is given to the foundry sand, and the foundry sand is lifted up, so that movement and aggregation can be easily and reliably performed. If the frequency is less than 25 Hz, the molding sand does not move, and if the frequency is 100 Hz or more, the molding sand does not follow and does not move. If the half amplitude is less than 0.01 mm, the molding sand does not move because it is too small, and the average diameter of the sand is 1.
If it exceeds 5 times, the foundry sand will splash and will not be aggregated.

When the inclination Θ (theta) of the axis of the Lissajous figure exceeds 75 degrees with respect to the XY plane, the horizontal movement of the foundry sand becomes inactive. Also in this case, the horizontal movement becomes inactive and the pushing force in the vertical direction becomes weak. If the value of the width W with respect to the length L is 0.5 or more, the molding sand draws a circle, and in this case, the substantial movement in the lateral direction becomes inactive.

Further, the change of the vibration component (vibration direction, frequency, phase difference, etc.) is continuously performed. This is because when the vibration is stopped and the movement of the foundry sand is stopped, even if the vibration is restarted, only the upper layer flows from the position where it had flowed before restarting, and the layer where aggregation stopped halfway was Will be formed. This creates a boundary in the foundry sand,
As a result, the strength of the foundry sand is reduced as a whole. Therefore, by continuously changing the vibration component such as changing the vibration direction, the generation of such a boundary layer is prevented, and the strength of the foundry sand is prevented from lowering.

[0017]

[0018]

Next, a vibration method according to the present invention will be described together with an apparatus for generating vibration.

FIG. 1 shows a vibration device. The vibration device 2
The piston-cylinder mechanisms 4, 6, 8 operating in the X, Y, Z axial directions, and the piston-cylinder mechanisms 4, 6,
The diaphragm 10 supported by the actuator 8 is provided, and the diaphragm 10 can be arbitrarily operated in each of the X, Y, and Z axial directions by operating the respective piston cylinder mechanisms 4, 6, 8. A joint 12 is provided for fixing in the XY plane and fixing in the Z-axis direction, and the joint 12 can be simultaneously moved in each direction by the clearance of the joint 12.

The vibration device 2 controls the hydraulic pressure of each of the piston-cylinder mechanisms 4, 6, 8 with a control device, and operates the vibration plate 10 so that the vibration locus of the vibration plate 10 has a desired shape. For example,
The vibration frequency and amplitude of each axis are set so that the trajectory of the vibration forms a Lissajous figure as shown in FIG. 2 in a plane in a predetermined direction passing through the Z axis.

By giving the molding sand vibrations whose trajectories form such a Lissajous figure, the molding sand in a mold frame (not shown) mounted on the diaphragm 10 is oriented in the direction synthesized by the XY components. And a component which vibrates also in the vertical direction is applied and densely aggregated. By rotating the vibration direction around the Z axis, the molding sand can be moved in any direction.

Specifically, the inclination Θ of the central axis of the figure is 45
When the width is 0.5 with respect to the length of the figure in the major axis direction, the molding sand can be moved very efficiently. After such vibration is rotated in an arbitrary direction about the Z-axis to move the molding sand sufficiently in the horizontal direction, the trajectory of the vibration is made circular or linear in the Z-axis direction. Then, the foundry sand is put in the vertical direction and can be strongly aggregated.

In the above example, the molding sand has been described as an example. However, the present invention is not limited to agglomeration of the molding sand, but may be applied to other powders.

Next, another example of the shaking table will be described.

The vibrating table includes a diaphragm 1 as shown in FIG.
0 is supported by six links 22.
By virtue of the function 2, the vibration table 10 can be moved and vibrated in any direction. A drive mechanism may be connected to the vibrating table 10 supported in this way to operate it.

The Lissajous figure drawn by the trajectory is shown in FIG.
However, the shape is not limited to an ellipse as shown in FIG.

[0027]

FIG. 4 shows the results of experiments on the flow of molding sand in each Lissajous figure for the trajectory of vibration. As shown in FIG. 4, the ratio between the axial length and the width of the Lissajous figure is 0.
In the case of 5 or less, it was confirmed that the molding sand moved in a predetermined direction and aggregated in the vertical direction. In addition, it was confirmed that the casting sand was uniformly and sufficiently aggregated by continuously changing the phase difference の between the vertical and horizontal vibrations.

[0028]

According to the vibration method of the present invention, the vibration applied to the molding sand can be the vibration obtained by adding the Z-axis component to the XY-axis components, thereby moving the molding sand in an arbitrary direction. At the same time, a force can be applied in the vertical direction, the molding sand can be densely agglomerated, and can be brought into close contact with the surface of the mold.

[Brief description of the drawings]

FIG. 1 is a diagram showing a vibration device.

FIG. 2 is a diagram showing a Lissajous figure;

FIG. 3 is a diagram showing another example of the vibration device.

FIG. 4 is a table showing experimental results.

FIG. 5 is a diagram showing a waveform of an acceleration.

FIG. 6 is a diagram showing a waveform of an acceleration in another example.

[Explanation of symbols]

 2 Vibration device 4, 6, 8 Piston cylinder mechanism 10 Vibration plate 12 Joint 22 Link

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yasuo Aoki 2-13-7 Midoricho, Koganei-shi, Tokyo (72) Inventor Akira Shigenobu 65, Taiocho, Kohoku-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-3-3 161145 (JP, A) JP-A-9-225586 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22C 11/00-25/00

Claims (3)

(57) [Claims] 1. A molding sand for synthesizing a vertical reciprocating vibration with a horizontal reciprocating vibration in an arbitrary direction in an XY plane and applying the synthesized vibration to a molding sand for casting to fasten the molding sand. In the vibration method, the vibration component of each of the reciprocating vibrations in the vertical direction and the horizontal direction is obtained by calculating the maximum value of acceleration from 4 m / s (square) to 30 m / s (2).
Squared) , and the waveform of the acceleration is a square wave or
Either the rising or falling side of the waveform stands almost vertically
Further, the sawtooth wave has a frequency of 25 to 100 Hz, a half amplitude of 0.01 mm to 1.5 times the diameter of the foundry sand, and a trajectory of a synthetic vibration obtained by synthesizing the reciprocating vibration. The inclination angle of the long axis of the Lissajous figure to be drawn is within a range of 15 degrees to 75 degrees with respect to the XY plane, and the width value with respect to the length in the long axis direction is 0 to 0.5. Method of vibrating foundry sand. 2. After applying the synthetic vibration according to claim 1,
A method for vibrating a foundry sand, wherein a vibration having a width value of about 1 with respect to the length of a Lissajous figure is applied. Wherein the reciprocating claims to characterized in that varied variations each value continuous vibration component of the vibration 1 or 2
The vibration method of the foundry sand according to the above.