JPH0871732A - Cooling method in casting - Google Patents

Abstract

PURPOSE: To prevent deformation of a casting by suitably adjusting retreating timing of an insert. CONSTITUTION: A molten metal is poured into a cavity 12 of a metal mold 1. Successively, an insert 13 is retreated at super slow speed V1 in X2 direction. In the initial phase, in which solidification is not progressed, the insert 13 is energized in X2 direction by repulsion force of molten metal, a pressure sensor 55 detects compression force. As solidification is considerably progressed, the repulsion force is eliminated, the tip part 13a of insert 13 is tightened toward center due to contraction force at solidification of molten metal to regulate retreating of the insert 13, the pressure sensor 55 detects tension force. As transforming timing to tension is taken for the reference, the insert 13 is retreated by the stroke set beforehand in arrow X2 direction, the cooling water of a second cooling chamber 15b is fed into the gap between a casting W and the tip part 13a of insert 13.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a cooling method in casting. INDUSTRIAL APPLICABILITY The present invention is suitable, for example, when an aluminum alloy is die-cast.

[0002]

2. Description of the Related Art In recent years, the present applicant has used a mold having a cavity for molding a casting and a movable insert, injecting the molten metal into the cavity of the mold, and partially melting the molten metal. A cooling method has been developed in which the nest is moved backward by a set stroke in consideration of the time, and cooling water is supplied to the gap generated thereby (Japanese Patent Publication No. 4-8138).

According to this method, the metal and the insert forming the casting can be forcibly cooled with the cooling water, so that the cooling time can be shortened and the casting cycle time can be shortened, and the overheating of the insert can be prevented. As a result, there is an advantage that the durability and life of the insert can be improved. Further, conventionally, in a die casting machine, the molten metal is injected into the cavity of the mold, the pressurizing pin is pushed into the molten metal in the cavity at a slow speed, and the pushing force is measured, whereby the progress of solidification of the molten metal is measured, Then, the preset value and the measured value are compared by a comparator, and when the measured value reaches the preset value, it is determined that the squeeze effect is optimum, and the pressure pin is pushed into the molten metal at a high speed,
A method for imparting a squeeze effect to the molten metal by this is disclosed (JP-A-4-182053). However, this method does not forcibly cool the pressure pin with cooling water even if the pressure pin is retracted.

[0004]

[Problems to be Solved by the Invention]
In the cooling method according to Japanese Patent No. 138, the timing of retracting the insert by the set stroke has a great influence on the accuracy of the shape of the metal forming the cast product, and also for cooling the metal forming the cast product and the insert. Have a big impact. Therefore, the timing of retracting the nest by the set stroke is important.

For example, if the timing of retracting the insert is too early, the degree of unsolidification of the molten metal is high, so that the shape of the cast product is deformed due to the influence of the melt casting pressure and the precision of the shape of the cast product is reduced. To do. If the timing is too late, the deformation of the cast product can be suppressed, but the forced cooling by the cooling water is delayed, so that the cooling effect is reduced and the production efficiency is reduced. Further, the amount of heat transferred from the molten metal to the insert increases, and the insert tends to reach a high temperature, which is disadvantageous in terms of the life of the insert.

The present invention has been made in view of the above circumstances, and the object of claims 1 and 2 is to deform the metal forming the cast product by optimizing the timing for retracting the nest. Another object of the present invention is to provide a cooling method in casting, which is advantageous in preventing the above-mentioned problems and can appropriately cool the metal and the insert forming the casting.

[0007]

According to a first aspect of the present invention, there is provided a cooling method in casting, comprising a molding die including a cavity for molding a cast product and a movable insert provided so as to be able to move forward and backward with respect to the cavity. By using the molten metal injected into the mold cavity, the insert is retracted by a set stroke to increase the gap between the metal forming the cast product and the insert in the cavity, and to fill the gap with cooling liquid. In a cooling method for casting by feeding and cooling, a metal that forms a cast product in the cavity after detecting the repulsive force against the nest due to the molten metal injected into the mold cavity and the repulsive force falls below a predetermined value It is characterized by retracting the nest by a set stroke.

According to a second aspect of the present invention, there is provided a cooling method in casting, wherein a molding die having a cavity for molding a cast product and a movable nest provided so as to be able to move forward and backward with respect to the cavity, and the nest is moved forward. Using a hydraulic cylinder device provided with a first oil chamber for generating hydraulic pressure and a second oil chamber for generating hydraulic pressure for retracting the insert, the insert is retracted by a stroke with the molten metal injected into the mold cavity. By increasing the gap between the metal forming the casting product and the insert in the cavity, the cooling liquid is fed to the gap to cool the casting method. By repeatedly releasing intermittently the hydraulic pressure of the first oil chamber of the hydraulic cylinder device in a state where the repulsive force against the nest is generated by the molten metal, the reciprocating movement of the nest in the forward direction and the backward direction is performed. Repeating, after the reciprocating movement amount is equal to or less than a predetermined value, it is characterized in that to set the stroke retract the insert to the metal to form the casting in the cavity.

[0009]

According to the method of the first aspect, the repulsive force of the molten metal injected into the cavity of the molding die against the nest is detected. Then, when the repulsive force becomes equal to or less than the predetermined value, it is determined that the solidification of the molten metal is appropriate, and the insert is retracted by the set stroke. With the backward movement, the gap between the metal forming the casting and the insert becomes larger, and the cooling liquid is fed into the gap.

According to the second aspect of the invention, the hydraulic pressure in the first oil chamber of the hydraulic cylinder device is intermittently released in a state where the molten metal is injected into the cavity of the forming die and a repulsive force is generated by the molten metal. Therefore, due to the repulsive force of the molten metal, the insert moves repeatedly in the forward and backward directions. Then, when the amount of reciprocating movement becomes less than or equal to a predetermined value, it is determined that the solidification of the molten metal is appropriate, and the nest is retracted by a set stroke. With the backward movement, the gap between the metal forming the casting and the insert becomes larger, and the cooling liquid is fed into the gap.

[0011]

【Example】

(Embodiment 1) Hereinafter, Embodiment 1 of the method of the present invention will be described with reference to FIGS. A mold 1 as a mold used in the method according to the present embodiment includes a movable mold 10, a fixed mold 11,
Cavity 12 for molding a casting, and metal movable insert 1 movably fitted in shaft hole 10a of movable mold 10.
3 and 3. The mold 1 has a cooling chamber 15 formed on the outer peripheral side of the insert 13. The cooling chamber 15 has an annular shape that continuously makes one round on the outer peripheral surface of the insert 13. Cooling room 1
5 is formed by the first cooling chamber 15a and the second cooling chamber 15b. The inner diameter of the second cooling chamber 15b is equal to that of the first cooling water chamber 15
It is set smaller than the inner diameter of a.

The mold 1 is equipped with a pumping means 3 and a water absorbing means 4 for circulating cooling water. Pumping means 3
Is formed by a water supply passage 30 connected to the cooling chamber 15 and the water source 32 of the mold 1, a pressure pump 31, and a water source 32 such as a water storage tank. The water absorbing means 4 is the cooling chamber 15 of the mold 1.
And the water suction passage 40 connected to the water source 32, and the water suction pump 41.
It is formed by. By the operation of the pumping means 3, the water source 3
The second cooling water is supplied to the cooling chamber 15 through the water supply passage 30 in the arrow E1 direction. By the operation of the water absorbing means 4, the cooling water in the cooling chamber 15 is returned to the water source 32 via the water absorbing passage 40.

A hydraulic cylinder device 5 is provided as an insert driving means for moving the insert 13 forward and backward along its axial direction. The hydraulic cylinder device 5 includes a cylinder 51 having a cylinder chamber 50, a piston 52 slidably arranged in the cylinder chamber 50, and a rod 53 connected to the piston 52. The piston 52 divides the cylinder chamber 50 into a first oil chamber 50h and a second oil chamber 50i. The first oil chamber 50h generates hydraulic pressure that moves the insert 13 forward in the arrow X1 direction. The second oil chamber 50i has a nest 13
Generates a hydraulic pressure that moves the arrow back in the direction of arrow X2. Rod 5
3 is divided into a first rod 53a and a second rod 53b, and at the boundary between the first rod 53a and the second rod 53b,
A pressure sensor 55 as a repulsive force detecting means is provided. The signal detected by the pressure sensor 55 is input to the control device 6 via the signal line 55k.

When the insert 13 is urged in the arrow X2 direction while the piston 52 is stopped, a compressive force acts on the pressure sensor 55, and conversely, the insert 13 moves in the arrow X1 direction. When it is pulled to, the pressure sensor 55 is subject to a pulling force. Further, in this embodiment, a hydraulic circuit 7 for driving the hydraulic cylinder device 5 is provided. The hydraulic circuit 7 includes an electromagnetic switching valve 70 having ports 70a to 70d, the switching valve 70, and the first oil chamber 50h of the cylinder chamber 50.
A first oil passage 71 that connects with the switching valve 70 and the cylinder chamber 5
The second oil passage 72 connecting the second oil chamber 50i of 0, the electromagnetic type flow control valve 73 having a throttle function arranged in the first oil passage 71, and the inflow of oil in the direction of the arrow N1 are permitted. A check valve 74 for preventing reverse flow is provided, a hydraulic pressure generation source 75 such as a hydraulic pump, and an oil open end 76 such as a reservoir. As can be understood from FIG. 1, the switching valve 70 has ports 70a and 70d communicating with each other and ports 70c and 70b.
Can be switched between a form F1 in which the ports 70a, 70b communicate with each other and a form F2 in which the ports 70c and 70d communicate with each other.

The control device 6 outputs a control signal for controlling the flow rate control valve 73 via a signal line 73k. The control device 6 outputs a control signal for controlling the switching valve 70 via the signal line 70k. Here, the first oil chamber 50 of the cylinder chamber 50
When the hydraulic pressure of h is P1 and the hydraulic pressure of the second oil chamber 50i is P2, in the case of P1> P2, the piston 52 and the insert 1
3 advances in the direction of arrow X1. On the contrary, when P1 <P2, the piston 52 and the insert 13 are retracted in the arrow X2 direction. Basically, based on the pressure difference between P1 and P2, the insert 13
The moving speed of is specified.

When casting, the cavity 12 of the mold 1 is used.
An aluminum-based molten metal is poured into the molten metal, and the molten metal surrounds the tip portion 13a of the insert 13. Injection is performed by the die casting method. At the time of injection, the pumping means 3 and the water absorbing means 4 are operated to circulate the cooling water from the water source 32 in the direction of the arrow E1 and allow the cooling water to flow into the cooling chamber 15. At this time, both the pressure feeding means 3 and the water supply means 4 operate simultaneously, so that the cooling water circulates smoothly.

Immediately after the injection of the molten metal, the control device 6 controls the switching valve 70 and the flow control valve 73 to control the operation of the hydraulic cylinder device 5, and the insert 13 is moved at the ultra-low constant speed V1 by the arrow X2. Retreat in the direction. At the initial stage when the solidification of the molten metal is not progressing, the molten metal moves the insert 13 to the arrow X.
The repulsive force that urges in two directions is large. This repulsive force is mainly based on the molten metal casting pressure. Since the die casting has a large molten metal injection pressure, the molten metal casting pressure is large and the repulsive force of the molten metal is also large. When the insert 13 is biased in the direction of the arrow X2 under the influence of the repulsive force of the molten metal, the pressure sensor 55 detects the compressive force. The compression signal of the pressure sensor 55 is output to the control device 6 via the signal line 55k.

By the way, as the solidification of the molten metal progresses, the repulsive force of the molten metal gradually decreases. When the solidification of the molten metal progresses considerably, the repulsive force decreases or disappears. When the molten metal further solidifies, the tip 13a of the insert 13 is tightened in the centripetal direction by the solidification contraction force of the molten metal, so that the retreat of the insert 13 is restricted, and thus the retreat of the second rod 53b is restricted. That is, although the first rod 53a tries to retreat at the ultra-low speed V1 by the operation of the hydraulic cylinder device 5,
Since the backward movement of the second rod 53b is restricted, the pressure sensor 55 detects the pulling force. The tension signal detected by the pressure sensor 55 is sent to the control device 6 via the signal line 55k as described above.
Is input to In this way, the progress of solidification of the molten metal in the cavity 12 is grasped based on the fact that the detection of the pressure sensor 55 is converted from the form of receiving the compressive force to the form of receiving the tensile force.

Even when the insert 13 is retracted to the predetermined position in the direction of arrow X2 at the ultra-low speed V1, if the pressure sensor 55 still detects the compressive force, that is, the tensile force When not converted into detection, the degree of unsolidification of the molten metal in the cavity 12 is still high. If the retracting of the insert 13 is further continued in this state, the shape of the cast hole formed by the insert 13 may collapse and the accuracy of the cast hole in the cast product may decrease. This is because the degree of unsolidification of the molten metal is still high and it is easily deformed by the molten metal casting pressure.
Therefore, the control device 6 controls the operation of the hydraulic cylinder device 5 by controlling the switching valve 70 and the flow rate control valve 73, advances the insert 13 at the speed V2 (V2> V1) in the arrow X1 direction, and Return to the position or near the original position. After that, the controller 13 causes the insert 13 to retreat again in the direction of the arrow X2 at the ultra-low constant speed V1. The backward / forward operation is repeated until the detection signal of the pressure sensor 55 changes from compression to tension.

If the pressure sensor 55 is converted from a form receiving a compressive force to a form receiving a tensile force, it means that the degree of solidification of the molten metal is considerably high. Therefore, the control device 6 controls the operation of the hydraulic cylinder device 5 and advances the insert 13 in the direction of the arrow X1 at the speed V2 or another speed as described above to re-form the casting hole. Further, the control device 6 controls the operation of the hydraulic cylinder device 5 and causes the insert 13 to move backward in the direction of arrow X2 at a speed V3 (V3> V1 or V3 = V2 may be set) by the set stroke.

Then, the metal forming the casting W and the insert 1
The gap between the tip end portion 13a of No. 3 and the tip end portion 13a becomes large. The cooling water in the second cooling chamber 15b is fed to the enlarged gap. Therefore, the metal forming the casting and the insert 13 are effectively forcibly cooled. Therefore, the life and durability of the insert 13 that is easily overheated because it is surrounded by the high-temperature molten metal can be improved. FIG. 2 shows a flowchart of main processing executed by the control device 6. As can be understood from FIG. 2, the molten metal is injected into the cavity 12 in step S102. In step S104, the set time t1 is waited. The waiting for the time t1 is in consideration of the filling of the molten metal in the cavity 12, the solidification start timing of the molten metal, and the like. In step S106, the operation of the hydraulic cylinder device 5 is controlled so that the insert 13 is retracted in the direction of arrow X2 at the ultra-low constant speed V1. In step S108, it is determined whether or not the detection of the pressure sensor 55 has changed from compression to tension. If NO, the process returns from step S108 to step S106, and the insert 13 is continuously retracted at the ultra-low constant speed V1 and conversion is continuously detected until conversion is performed.
If YES in step S108, step S108
The process proceeds from step 108 to step S110, and it is determined whether the time t2 has elapsed from the time of conversion. If NO, the process proceeds to step S112, the insert 13 is moved forward in the direction of the arrow X1 in order to re-form the casting hole, the process returns from step S112 to step S106, and the insert 13 is again moved at a super-low constant speed. It is retracted in the direction of arrow X2 at V1. At this time, since the tension mode has already been converted, the process proceeds from step S108 to step S110.

If the result of determination in step S110 is that time t2 has elapsed, step S110 advances to step S114, in which the insert 13 is retracted by the set stroke. As a result, as described above, a gap is formed between the metal forming the casting and the tip portion 13a of the insert 13, and the cooling water is supplied to the gap. Note that waiting for time t2 is
This is because the solidification of the cast product is promoted and the precision of the cast product, especially the casting hole thereof, is ensured. The order is not limited to the order of the flowchart shown in FIG.
You may decide to proceed directly to 14. This flow chart may be executed by a sequencer also called a programmable controller or may be executed by using a microcomputer.

As described above, according to the present embodiment, after the detection by the pressure sensor 55 is changed from the compression form to the tension form and the repulsive force by the molten metal becomes less than a predetermined value, the insert 13 is set by the set stroke. The timing is to move backward. This makes it possible to optimize the timing for retracting the insert 13 by a set stroke, which is advantageous in preventing the deformation of the metal forming the cast product, and the accuracy of the shape of the cast product, especially the casting formed by the insert 13. This is advantageous for ensuring the accuracy of the punched holes. Further, the timing of forcibly cooling the metal forming the casting and the insert 13 can be optimized.

Further, according to this embodiment, when the insert 13 retracted at the ultra-low speed V1 reaches a predetermined position, the insert 13 is advanced again, so that the casting hole is reshaped. This is advantageous in reducing or avoiding the collapse of the shape of the casting hole in the cast product, and is more advantageous in ensuring the precision of the casting hole. Further, according to the present embodiment, the insert 13 is moved forward again to press the metal forming the cast product, so that the forging effect and the squeeze effect of the metal forming the cast product can be expected. Therefore, it is advantageous for reducing and avoiding defects such as shrinkage cavities and microporosity in the metal structure of the cast product. Furthermore, the metal forming the cast product is effectively brought into close contact with the mold surface of the cavity 12, which is advantageous for reducing and avoiding the air gap, and the cooling rate of the metal forming the cast product is increased accordingly, resulting in a dense metal structure. It is advantageous to

In the above example, the time point when the pressure sensor 55 detects the compression mode is changed to the tension mode, and the timing for retracting the insert 13 by the set stroke is used as a reference. However, depending on factors such as the material of the molten metal, the difference in the molten metal temperature, the amount and shape of the molten metal, the progress of solidification of the molten metal is slow,
Even if the insert 13 is continuously retracted in the direction of the arrow X2 at the speed V1 for a predetermined time, the detection of the pressure sensor 55 may not be converted from the compressed form to the pulled form. In this case, the nest 13
If the temperature is further retreated, the degree of unsolidification of the molten metal is high, and thus the accuracy of the shape of the casting hole may be reduced. In this case, the insert 13 is advanced in the arrow X1 direction, and the insert 13 is retracted again from the advanced position in the arrow X2 direction at the speed V1. This is continued until the detection of the pressure sensor 55 changes from the compressed form to the tension form. When the compression mode is converted to the tension mode, the timing for retracting the insert 13 by the set stroke in the direction of arrow X2 is set in the same manner as described above.

In the above embodiment, the insert 13 is moved to the arrow X2.
If the amount of retreat exceeds a certain value when retreating at a super-low speed V1 in the direction, the gap between the metal forming the casting W and the tip 13a of the insert 13 becomes large, and the metal and the insert 13
The cooling water in the storage chamber 15 may enter between the tip end portion 13a and the tip end portion 13a. In this case, when the insert 13 moves forward again, the insert 13 presses the metal forming the casting through the cooling water that has entered, and the cooling effect is further secured. Further, the water pressure of the cooling water that has entered the gap acts not only in the axial direction of the insert 13 but also outward in the radial direction when the insert 13 moves forward, so the forging effect is also improved.

(Second Embodiment) A second embodiment will be described with reference to FIGS. 3 and 4. The second embodiment has basically the same configuration as the first embodiment. The second embodiment is also equipped with the same pumping means 3 and water absorbing means 4. Also in the second embodiment, basically, the same effect as that of the first embodiment is obtained, and the cooling water is fed between the metal forming the casting product and the insert 13, so that the metal forming the casting product is inserted. Forced cooling with the tip portion 13a of the child 13 is effectively performed.

Also in this example, the hydraulic cylinder device 5 is provided. The hydraulic cylinder device 5 is provided with a position sensor 58 that detects displacement of the insert 13 in the axial direction. The signal from the position sensor 58 is input to the control device 6 via the signal line 58k. Furthermore, a hydraulic circuit 7 for driving the hydraulic cylinder device 5 is provided. The hydraulic circuit 7 is an electromagnetic switching valve 7 having ports 70a to 70d.
0, a first oil passage 71 that connects the switching valve 70 and the first oil chamber 50h, a second oil passage 72 that connects the switching valve 70 and the second oil chamber 50i, a hydraulic pressure generation source 75, and an oil open end. And 76.

When casting, the cavity 12 of the mold 1
An aluminum-based molten metal is injected by die casting. At the time of injection, as in the case of the first embodiment, the pumping means 3 and the water absorbing means 4 are operated to allow the cooling water from the water source 32 to flow into the cooling chamber 15. In the initial stage where the solidification of the molten metal in the cavity 12 has not progressed, the insert 13 is urged in the direction of the arrow X2 under the influence of the repulsive force of the molten metal. At this time, the control device 6 causes the switching valve 70 to switch, and the first oil passage 71
And the ports 70a and 70d are communicated with each other, the first oil chamber 5
Since 0h communicates with the oil open end 76, the pressure in the first oil chamber 50h decreases, and the forward hydraulic pressure in the first oil chamber 50h is released. Therefore, the repulsive force due to the molten metal overcomes the pressure in the first oil chamber 50h, and the insert 13 naturally retracts in the direction of the arrow X2. The amount of retreat is detected by the position sensor 58 and input to the control device 6 via the signal line 58k.

When the nest 13 is naturally retracted to the predetermined position,
The control device 6 causes the switching valve 70 to switch, and the first oil passage 71
To communicate with the ports 70a and 70b, and the first oil chamber 50h
Is communicated with the hydraulic pressure generation source 75. Therefore, the oil pressure source 75
Oil is supplied to the first oil chamber 50h of the hydraulic cylinder device 5, the oil pressure of the first oil chamber 50h increases, and the oil pressure of the first oil chamber 50h overcomes the repulsive force of the molten metal, which causes the nest 13 to move in the arrow direction. Move forward in the X1 direction. The amount of forward movement is detected by the position sensor 58 and input to the control device 6 via the signal line 58k. When the nest 13 reaches the predetermined forward position,
When the control device 6 operates the switching valve 70 to switch the oil passage 71 and the ports 70a and 70d to communicate with each other, and the pressure of the first oil chamber 50h is communicated to the oil open end 76 again, the first oil chamber 50h advances. Hydraulic pressure is released. Therefore, the repulsive force of the molten metal overcomes the pressure in the first oil chamber 50h, and the insert 13 naturally retreats again in the direction of arrow X2.

Such natural retreat and forward movement by the hydraulic pressure of the first oil chamber 50h, that is, reciprocating movement are repeated. As the solidification of the molten metal progresses, the repulsive force due to the molten metal decreases or disappears, so the amount of spontaneous retreat of the insert 13 gradually decreases and the amount of reciprocating movement of the insert 13 also decreases. When the amount of reciprocating movement of the insert 13 becomes substantially zero, it is determined that the degree of solidification of the molten metal in the cavity 12 is appropriate, and it is time to send the cooling water to the gap, and the insert 13 is set. Stroke backwards.

With the backward movement of the set stroke, the metal forming the casting W and the tip 13a of the insert 13 are formed.
And the cooling water in the cooling chamber 15 is fed to the increased clearance. Therefore, the metal forming the casting and the tip 13a of the insert 13 are forcibly cooled as in the first embodiment. As described above, according to the second embodiment, by intermittently releasing the hydraulic pressure in the first oil chamber 50h of the hydraulic cylinder device 5, the reciprocating movement of the insert 13 can be repeated using the repulsive force of the molten metal. it can. Then, when the amount of reciprocating movement becomes substantially zero, it is determined that it is the timing to send the cooling water. With such a criterion, the timing for retracting the insert 13 by the set stroke can be optimized, which is advantageous in preventing the deformation of the metal forming the cast product. Further, the timing of supplying the cooling water to the boundary between the metal forming the casting and the insert 13 can be optimized.

Further, since the reciprocating movement of the insert 13 is repeated,
This is advantageous for re-forming the casting hole, for reducing or avoiding the collapse of the shape of the casting hole in a cast product, and for ensuring the accuracy of the casting hole. Further, the metal forming the cast product may have a large degree of tightening the tip portion 13a of the insert 13 by the solidification shrinkage force. For example, the tip 1 of the insert 13
When the escape gradient of 3a is small or substantially absent, the degree of tightening is large. Further, when the cast product is thick and the tightening force due to the solidification shrinkage force is large, the degree of tightening is large. In such a case, smooth natural retraction of the insert 13 may be hindered. In this regard, in the second embodiment,
Since the reciprocating movement of the insert 13 is frequently repeated from a state in which the degree of unsolidification of the molten metal is high to a state in which the solidification has progressed considerably, the natural retreat of the insert 13 is easily secured even if the solidification of the molten metal progresses. Therefore, even if the tip end portion 13a of the insert 13 has a small or substantially no slope, the insert 13 is naturally retracted. Therefore, it is suitable for forming a cast hole having a small or substantially no draft in a cast product.

Since the reciprocating movement of the insert 13 is repeated,
Since the metal forming the cast product is repeatedly pressed, a forging effect, a molten metal forging effect, and a squeeze effect can be expected. Therefore, it is advantageous in reducing or avoiding defects such as shrinkage cavities and microporosity in the metal structure of the cast product, and further, the metal forming the cast product is effectively brought into close contact with the mold surface of the cavity 12,
This is advantageous in reducing or avoiding the air gap, and thus the cooling rate of the metal forming the cast product is faster, which is advantageous in densifying the metal structure.

FIG. 4 shows a flowchart of the main processing executed by the control device 6. The molten metal is injected into the cavity 12 in step S202. Set time t1 in step S204
stand by. The waiting for the time t1 is in consideration of the filling of the molten metal in the cavity 12, the solidification start timing of the molten metal, and the like. In step S206, the hydraulic pressure of the hydraulic cylinder device 5 is intermittently interrupted to intermittently release the forward hydraulic pressure of the first oil chamber 50h. In step S208, the size of the natural retreat amount of the insert 13 is determined. If the natural retreat amount is larger than the predetermined value, it is determined that the solidification of the molten metal is insufficient, and step S2
Proceeding to 06, the hydraulic pressure of the first oil chamber 50h of the hydraulic cylinder device 5 is intermittently released. When the natural retreat amount becomes substantially zero, the process proceeds to step S210, and the insert 13 is retracted by the set stroke. As a result, a gap is formed between the metal forming the casting and the tip 13a of the insert 13,
Cooling water is supplied to the gap.

In the second embodiment described above, when the reciprocating amount of reciprocating movement of the insert 13 exceeds a certain value, the cast product W is obtained.
The gap between the metal forming the and the tip 13a of the insert 13 becomes large, and the cooling water of the storage chamber 15 may enter between the metal and the tip 13a of the insert 13. In this case, when the insert 13 moves forward again, the insert 13 presses the metal forming the casting through the cooling water that has entered, and the cooling effect is further secured.

Also in this example, when the backward movement amount of the reciprocating movement amount of the insert 13 exceeds a certain value, the gap between the metal forming the casting W and the tip 13a of the insert 13 becomes large. Therefore, the cooling water in the storage chamber 15 may enter between the metal and the tip 13a of the insert 13. In this case, when the insert 13 moves forward again, the insert 13 presses the metal forming the casting through the cooling water that has entered, and the cooling effect is further secured. Further, the water pressure of the cooling water that has entered the gap acts not only in the axial direction of the insert 13 but also outward in the radial direction when the insert 13 moves forward, so the forging effect is also improved.

(Other Example) In the first embodiment, the pressure sensor 55 is used.
After the detection of is converted from the compressed form to the tension form, the nest 1
3 is set back by the set stroke. However, the invention is not limited to this, and when the compression force detected by the pressure sensor 55 becomes equal to or less than a predetermined value, the insert 13 may be retracted by the set stroke. In short, when the repulsive force due to the molten metal becomes equal to or less than the predetermined value, the insert 13 is retracted by the set stroke.

In each of the above-mentioned examples, the insert 13 forms a casting hole in the cast product, but the present invention is not limited to this, and the insert need not form a casting hole.
In short, the insert may be one that faces the molten metal in the cavity and receives a repulsive force from the molten metal. Although aluminum is used as the molten metal in each of the above-described examples, the present invention is not limited to this, and other metals such as zinc, cast iron, cast steel, and titanium may be used. Although the molten metal is die-casted in each of the above examples, the present invention is not limited to this, and low-pressure casting or gravity casting may be used.

(Supplementary Note) The following technical idea can be understood from the above-described embodiments. The mold according to claim 1 or 2, wherein the mold is equipped with a cooling liquid supply means, and the cooling liquid supply means comprises a pressure supply means for supplying the cooling liquid between the metal forming the casting and the insert. And a suction means for sucking and discharging the cooling liquid between the metal forming the casting and the insert.

[0041]

According to the methods of claims 1 and 2, it is possible to achieve appropriate timing for retracting the nest. Therefore, it is possible to prevent the timing of retracting the insert from being too early, it is advantageous to prevent the deformation of the metal forming the cast product, and it is advantageous to ensure the accuracy of the shape of the cast product. Further, since the timing is appropriate, the metal forming the cast product and the insert can be appropriately cooled in a short time, the cooling time can be shortened, the production efficiency is improved, and the insert is It is advantageous in terms of durability and life.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment.

FIG. 2 is a flowchart executed by the control device according to the first embodiment.

FIG. 3 is a configuration diagram of a second embodiment.

FIG. 4 is a flowchart executed by a control device according to a second embodiment.

[Explanation of symbols]

In the figure, 1 is a mold (molding die), 12 is a cavity, 13 is an insert, 5 is a hydraulic cylinder device, 55 is a pressure sensor, 6 is a control device, and 70 is a switching valve.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Mitsuru Inui 1-9-6 Rokujo Minami Gifu City, Gifu Prefecture Gifu Seiki Kogyo Co., Ltd. 1st Division (72) Kento Nimura 1 Rokujo Minami Gifu City, Gifu Prefecture 9-6 Gifu Seiki Industry Co., Ltd. 1st Business Division (72) Inventor Akira Saito 1-9-6 Rokujo Minami, Gifu City, Gifu Prefecture Gifu Seiki Industry Co., Ltd. 1st Business Division

Claims (2)

[Claims] 1. A molding die comprising a cavity for molding a cast product and a movable insert provided so as to be able to move forward and backward with respect to the cavity, wherein molten metal is injected into the cavity of the molding die. By cooling the insert by a set stroke, the gap between the metal forming the casting product in the cavity and the insert is enlarged, and a cooling liquid is supplied to the gap to cool the insert. In the method, the repulsive force of the molten metal injected into the cavity of the molding die against the insert is detected, and after the repulsive force becomes a predetermined value or less, the insert against the metal forming the casting product in the cavity. Is set back by the set stroke, a cooling method in casting. 2. A molding die having a cavity for molding a cast product and a movable insert provided so as to be able to move forward and backward with respect to the cavity, and a first oil for generating a hydraulic pressure for moving the insert forward. By using a hydraulic cylinder device including a chamber and a second oil chamber that generates a hydraulic pressure for retracting the insert, by retracting the insert by a set stroke in a state where molten metal is injected into the cavity of the mold, In a casting cooling method in which a gap between a metal forming a cast product and the insert in the cavity is enlarged, and a cooling liquid is supplied to the gap for cooling, it is injected into the cavity of the mold. By repeating intermittent release of the hydraulic pressure of the first oil chamber of the hydraulic cylinder device while the repulsive force generated by the molten metal against the nest is generated, the reciprocating movement of the nest in the forward and backward directions is repeated. After reciprocating movement amount is equal to or less than the predetermined value, the cooling method in the casting, characterized in that to said set stroke retracted 該入Ko against the metal forming the the cast product in the cavity.