JP2006289393A - Sprue insert for casting mold, casting mold provided with the sprue insert, and casting apparatus provided with the casting mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new configuration considering problems on a ceramic raw material working and on shocking resistance with respect to a sprue insert applying the ceramic raw material. <P>SOLUTION: The sprue insert 20 is provided in a molten metal inlet of the casting mold, and is composed of: a cylindrical upper side gate insert 20A constituted of the ceramic raw material; and a cylindrical lower side gate insert 20B connected to the lower part of the upper side gate insert 20A at the upper part thereof. A packing 22 is inserted between the upper side gate insert 20A and the lower side gate insert 20B. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a casting mold used in a suction casting method and a low pressure casting method, and more particularly to a structure of a gate insert of a casting mold.

Conventionally, in the mold entrance of the casting mold used in the differential pressure casting method such as the suction casting method and the low pressure casting method, the ceramic material is applied in consideration of the resistance to erosion and wear resistance to the molten metal. The technology relating to the entrance of the gate using this ceramic material is also well known (for example, see Patent Documents 1 and 2).
As disclosed in these documents, the pouring gate insert is integrally configured as a multiple structure of an inner cylinder made of a ceramic material and a metal outer cylinder, and the inner cylinder is made of molten metal. It has a structure that functions as a passage to be passed.

In addition to making the gate entrance made of ceramic material, the coating material (molding material) containing ceramic powder is sprayed onto the entrance entrance to coat the surface of the entrance entrance to prevent melting damage. It was broken.
Japanese Utility Model Publication No. 5-76660 Japanese Utility Model Publication No. 5-13641

However, in the case of a multi-structured one-piece structure, such as a conventional gate entrance structure, in order to prevent the molten metal from leaking, the clearance with the outer cylinder must be set strictly. For example, an inner cylinder made of a ceramic material requires high-precision processing. In addition, complicated and high-precision processing of hard ceramic materials is costly.
Further, in the case where the inner cylinder is formed of a ceramic material, there is a drawback that when the size is increased, the inner cylinder is easily damaged by a thermal shock or a physical shock.

  On the other hand, since the coating on the surface of the above-mentioned gate entrance comes into contact with the molten metal and wears out, it is necessary to apply a coating material every several tens of shots. And it was necessary to stop an apparatus for this application | coating operation | work, and there existed a problem that manufacturing efficiency fell.

  Therefore, the present invention proposes a novel configuration in consideration of the problem of processing of the ceramic material and the problem of impact resistance with respect to the gate entrance to which the ceramic material is applied.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, as described in claim 1, a pouring gate insert provided at a molten metal inlet of a casting mold, a cylindrical upper weir insert made of a ceramic material, and an upper portion of the upper weir insert And a bottom dam insert of a cylindrical mold connected to the lower portion of the mold.

  Further, as described in claim 2, a packing is sandwiched between the upper weir insert and the lower weir insert.

  In addition, as described in claim 3, the packing has thermal expansibility.

  Further, as described in claim 4, the upper and lower through-holes of the upper weir insert are configured such that the inner diameter decreases from the upper opening to a midway portion at a predetermined depth in the lower direction, Suppose that it is comprised so that an internal diameter may become large from a middle part to a lower opening part.

  Moreover, it is set as the casting metal mold | die provided with the said gate entrance as described in Claim 5.

  According to a sixth aspect of the present invention, there is provided a casting apparatus comprising the casting mold according to the sixth aspect, wherein the molten metal is introduced into the cavity of the casting mold through the gate insert by a differential pressure. A differential pressure adjusting device for supplying the cooling mold, a cooling device for supplying a coolant to a cooling circuit provided in the movable mold and the fixed mold of the casting mold, and moving the movable mold to solidify the solidified product. An actuator that is removed from the fixed mold, a differential pressure adjusting device, a cooling device, and a control device that controls the operation of the actuator are provided.

  Further, as described in claim 7, the control device performs cooling control by the cooling device so as to solidify the molten metal in a range above the midway portion of the upper weir insert, and from the midway portion. When the molten metal solidifies in the upper range, the supply of the molten metal into the cavity by the differential pressure adjusting device is stopped.

  In the invention described in claim 1 above, since only the upper weir insert is made of a ceramic material, compared to the case where the entire gate entrance is made of a ceramic material, Miniaturization can be achieved, and the probability of occurrence of problems such as thermal shock and damage to ceramic materials due to physical shock can be reduced. In other words, it can overcome the disadvantages of ceramic materials that are vulnerable to impact. Further, if the lower weir insert is made of metal, the lower weir insert can be processed with high accuracy while keeping the processing cost low.

  Moreover, in invention of Claim 2, it can prevent that the molten metal which passes a gate spigot leaks outside from the junction part of an upper weir insert and a lower weir insert.

  Moreover, in invention of Claim 3, the sealing property in a high temperature environment can be improved, and the leak of a molten metal can be prevented reliably.

  Further, in the invention according to claim 4, if the molten metal is solidified in a range above the midway part, the joint part that becomes a parting part of the upper weir piece and the lower weir piece is a product. Since the position is lower than the weir part, the molten metal is inserted into the joint part, the inserted part is torn off at the time of demolding, the product weir part is damaged, and the mold release resistance is increased. Can be prevented.

  Further, in the invention according to claim 5, since the upper weir insert is made of a ceramic material, the product weir portion is easily removed from the upper weir insert, and the entire gate entrance is made of metal. In comparison, demolding can be performed at an early stage.

  In the invention according to claim 6, a series of casting processes of product forming, cooling, and demolding can be performed by automatic control by the control device.

  Further, in the invention according to claim 7, since the molten metal is solidified in the range above the midway part, the product weir part configured in the upper weir insert can be extracted upward. Become.

As shown in FIG. 1, a casting mold 1 according to the present invention is composed of a movable mold 11 and a fixed mold 12, and a cavity 13 is formed inside when both are attached. .
A cylindrical gate 20 is provided at the lower center of the fixed mold 12. The gate insert 20 is provided with an upper and lower through hole 20a penetrating in the vertical direction in the figure, and the molten metal 16 is supplied into the cavity 13 through the upper and lower through hole 20a.
Further, cooling circuits 17 and 17 to which a coolant is supplied from a cooling device 26 are provided inside the movable mold 11 and the fixed mold 12, and after the supply of the molten metal 16 is completed, the molten metal 16 is cooled. It is trying to solidify. Further, the solidification of the molten metal 16 proceeds sequentially from the upper side to the lower side in the figure, and the molten metal 16 in the upper and lower through holes 20a of the pouring gate insert 20 is finally solidified.

Moreover, as shown in FIG. 1, the casting mold 1 according to the present invention is installed in, for example, a casting apparatus 10 that performs a low-pressure casting method.
The casting apparatus 10 is provided with a molten metal holding furnace 2 for containing a molten metal 16, and high pressure air is supplied into the molten metal holding furnace 2 from a differential pressure adjusting device 25 serving as a high pressure air supply source. The molten metal 16 in the stalk 3 (pouring pipe) is pushed upward by air. The molten metal 16 pushed up is supplied into the cavity 13 through the gate insert 20.
The casting apparatus 10 is provided with an actuator 4, and the movable mold 11 is moved in the vertical direction in the figure by the actuator 4.
The casting mold 1 according to the present invention can be applied to other differential pressure casting methods such as a suction casting method in addition to the low pressure casting method.

Further, as shown in FIG. 2, a gate entrance 20 provided at the molten metal entrance of the casting mold 1 is attached to a through hole 12a provided in the vertical direction in the figure in the fixed mold 12 and is made of ceramic such as aluminum titanate. A cylindrical upper weir 20 </ b> A composed of a material, and a cylindrical lower weir 20 </ b> B whose upper part is connected to the lower part of the upper weir 20 </ b> A and whose lower part is connected to the lower part of the stalk 3. , Is composed of.
The lower weir insert 20 </ b> B is configured to be sandwiched between the lower surface 12 u of the fixed mold 12 and the upper surface 18 u of the holding furnace upper lid 18 of the molten metal holding furnace 2.

  In this configuration of the gate entrance 20, only the upper weir insert 20 </ b> A is made of a ceramic material, and therefore, compared to the case where the entire gate entrance 20 is made of a ceramic material, Miniaturization can be achieved, and the probability of occurrence of problems such as thermal shock and damage to ceramic materials due to physical shock can be reduced. In other words, it can overcome the disadvantages of ceramic materials that are vulnerable to impact.

The ceramic material constituting the upper weir insert 20A uses a highly durable ceramic material such as aluminum titanate or alumina, and has resistance to erosion that is difficult to bond with molten metal (poor wettability). It is also conceivable to apply highly durable chromia (chromium oxide) having excellent wear resistance. Thereby, the melting damage to the molten metal of the upper weir insert 20A can be prevented.
For the lower weir insert 20B, for example, it is conceivable to use the same plastic steel as the metal of the casting mold, but it is not particularly limited.

The surface roughness of the inner surface of the upper weir 20A is set to be approximately 10 μm or less in terms of the ten-point average roughness (Rz).
By setting such surface roughness, the friction generated between the inner surface of the upper weir 20 A and the molten metal 16 is reduced. By reducing the friction, as shown in FIG. 1, the progress of wear on the inner surface of the upper weir 20 </ b> A is suppressed in the supplying process of the molten metal 16.
Further, as shown in FIG. 4B, since the friction generated between the product weir 16a and the upper weir 20A is reduced at the time of releasing the product 16A after the molten metal is solidified, so-called mold release is achieved. The resistance can be reduced, and problems such as peeling off the surface of the product weir 16a are prevented.
The specific polishing method for setting the surface roughness to a predetermined value is not limited to a special method, and a polishing method suitable for polishing the ceramic material surface is applied. .

Further, as shown in FIG. 2, a flange portion 20f facing the lower surface 12u of the fixed mold 12 is provided at the lower portion of the upper weir 20A, and the flange at the upper portion of the lower weir 20B. A flange accommodating portion 20s that surrounds the periphery of the portion 20f and forms an annular space 20k between the flange portion 20f and the lower surface 12u is provided, and a packing 22 having a thermal expansion property is sandwiched in the annular space 20k. It is configured to be worn. That is, the packing 22 is sandwiched between the upper weir 20 A and the lower weir 20 B.
Further, as shown in FIG. 2, a flange portion 20g to be attached to the upper surface 18u of the holding furnace upper lid 18 is provided at the lower portion of the lower weir 20B, and the holding furnace upper lid 18 and the flange portion 20g are provided. The gap between the lower weir inserts 20B is sealed.

In this configuration, the packing 22 can prevent the molten metal 16 passing through the gate insert 20 from leaking to the outside from the joint portion 20v of the upper weir insert 20A and the lower weir insert 20B. Further, by using the thermally expandable packing 22 that is expanded by the heat transmitted from the upper weir 20A, the sealing property of the space 20k in a high temperature environment can be improved, and the molten metal 16 can be surely leaked. Can be prevented.
The material of the packing 22 is not particularly limited, but expands due to heat transmitted from the upper weir 20A, and fills the gap of the space 20k, so that the molten metal 16 from the joint 20v to the outside is expanded. It is desirable to prevent leakage and have sufficient heat resistance.

Moreover, if the whole is made of a ceramic material without dividing the gate entrance 20 into upper and lower parts, the molten metal is provided for the flange accommodating portion 20s and the flange portion 20g of the lower weir insert 20B. There is a problem that high-precision processing is required to prevent the metal 16 from leaking, and high-precision processing of a hard ceramic material is expensive.
In this regard, as in the configuration of the present invention, the gate entrance 20 is divided into two parts, and the lower weir insert 20B is made of metal. High-precision machining can be performed while keeping the machining cost low, and cost problems can be avoided.

  As shown in FIG. 3A, the shape of the flange accommodating portion 20s is such that it has an upright wall surface, and the packing 22 is connected to the lower surface 12u of the fixed mold 12 as shown in FIG. It is good also as a stepped shape which has the horizontal part 20t pinched | interposed between. In addition, the packing 22 may be sandwiched between the joints 20v.

  Further, as shown in FIGS. 2 and 3A, the upper and lower through holes 20a of the upper weir 20A have an inner diameter extending from the upper opening 20x to a midway portion 20c at a predetermined depth D in the lower direction. Is configured such that the inner diameter gradually increases from the midway portion 20c to the lower opening portion 20u, and the upper opening portion 20y of the lower weir insert 20B is attached to the lower opening portion 20u. It is going to be done. The predetermined depth D is not particularly limited. For example, the predetermined depth D is 2 in the overall length of the upper weir 20A in terms of forming the product weir 16a shown in FIG. It is preferable to set a sufficient depth such as ensuring / 3 or more.

In this configuration, as shown in FIG. 4 (a), if the molten metal 16 is solidified in the range above the midway portion 20c, the parting portions of the upper weir piece 20A and the lower weir piece 20B Since the joining portion 20v is located below the product weir portion 16a, the molten metal 16 is inserted into the joining portion 20v, and the inserted portion is torn off during demolding, so that the product weir portion 16a is formed. Problems such as damage and increased mold release resistance can be prevented.
Note that it is not preferable to dispose the joint 20v between the upper opening 20x (see FIG. 3A) and the midway portion 20c because the product weir 16a may be broken at the time of demolding. It can be said.

Further, as shown in FIG. 4B, since the upper weir 20A is made of a ceramic material, the product weir 16a can be easily removed from the upper weir 20A, and the entire gate entrance is made of metal. Demolding can be carried out at an early stage as compared with the case of doing so.
That is, the product dam 16a has the latest time to complete solidification, and in order to perform demolding without damaging the product dam 16a, it is necessary to wait until the solidification of the product dam 16a is completed. As described above, by reducing the friction between the surface of the product weir 16a and the upper weir 20A, the product weir 16a can be used even when the waiting time is shortened compared to the case where the friction is large. Can be reduced.
For example, in the past, the time required from the start of the casting process to demolding is about 300 seconds in total, and the waiting time is about 30 seconds, which has become a bottleneck for shortening the casting time. According to the present invention, the waiting time can be shortened to about half of 15 seconds, and a total reduction of 15 seconds can be achieved.
As described above, by shortening the standby time, it is possible to perform early mold release, and by this early mold release, the casting time for each shot is shortened and the production efficiency is improved.

  Further, since the ceramic material of the upper weir 20A has high durability, the coating material is not frequently applied as in the case of the conventional spraying of the coating material (coating material). Efficiency is improved (leading to improvement of so-called MTBF).

  FIG. 1 shows an example of the configuration of a casting apparatus 10 provided with a casting mold 1 provided with the above-described gate entrance 20. The molten metal 16 is fed through the gate entrance 20 by a differential pressure. Then, the coolant is supplied to the differential pressure adjusting device 25 for supplying the casting mold 1 into the cavity 13 and the cooling circuits 17 and 17 provided in the movable mold 11 and the fixed mold 12 of the casting mold 1. For controlling the operation of the cooling device 26, the actuator 4 for moving the movable die 11 and releasing the product 16A from the fixed die 12, the differential pressure adjusting device 25, the cooling device 26, and the actuator 4. And a device 30. With this configuration, a series of casting steps of molding, cooling, and demolding of the product 16A can be performed by automatic control by the control device 30.

And the said control apparatus 30 performs cooling control by the said cooling device 26 in order to solidify the molten metal 16 in the range above the middle part 20c of the said upper weir insert 20A, and the said in the said upper weir insert 20A When the molten metal 16 solidifies in the range above the midway portion 20c, the supply of the molten metal 16 into the cavity 13 by the differential pressure adjusting device 25 is stopped. Since the molten metal 16 is solidified in the range above the midway portion 20c by the control by the control device 30, the product weir portion 16a configured in the upper weir insert 20A can be extracted upward. (See FIG. 4B).
Whether the molten metal 16 is solidified by the control device 30 is determined based on the cooling time of the molten metal 16 by the cooling device 26, or a separate sensor is provided to determine whether the upper weir 20A is solidified. It is conceivable to detect and judge, and is not limited to a specific method.

The figure shown about the metal mold | die for casting provided with the gate insert concerning this invention, and the structure of a casting apparatus. Side surface sectional drawing shown about the structure of the entrance gate which concerns on this invention. (A) is a figure shown about the 1st structural example of the flange accommodating part of a lower weir insert. (B) is a figure similarly shown about a 2nd structural example. (A) is a figure which shows that a product dam part is solidified above the middle part of an upper dam insert. (B) is a figure shown about the state from which a product dam part is demolded.

Explanation of symbols

12 Fixed type 20 Mouth insert 20A Upper weir insert 20B Lower weir insert 22 Packing 20c Midway

Claims (7)

A pouring gate provided at the molten metal inlet of the casting mold,
A casting mold gate insert composed of a cylindrical upper weir insert composed of a ceramic material and a cylindrical lower weir insert connected to the lower portion of the upper weir insert. .   The pouring gate insert for a casting mold according to claim 1, wherein a packing is interposed between the upper weir insert and the lower weir insert.   The gate of the casting mold according to claim 2, wherein the packing has a thermal expansion property.   The upper and lower through-holes of the upper weir insert are configured such that the inner diameter decreases from the upper opening to a midway portion at a predetermined depth in the lower direction, and the inner diameter increases from the midway portion to the lower opening. The pouring gate insert for a casting mold according to any one of claims 1 to 3, characterized by comprising:   A casting mold comprising the pouring gate insert of the casting mold according to any one of claims 1 to 4. A casting apparatus comprising the casting mold according to claim 5,
A differential pressure adjusting device for supplying the molten metal into the cavity of the casting mold through the gate insert by a differential pressure;
A cooling device for supplying a coolant to a cooling circuit provided in the movable mold and the stationary mold of the casting mold;
An actuator that moves the movable mold and demolds the solidified product from the fixed mold;
A controller for controlling the operation of the differential pressure adjusting device, the cooling device, and the actuator;
A casting apparatus comprising a casting mold comprising:   The control device performs cooling control by the cooling device so as to solidify the molten metal in a range above the midway part of the upper weir insert, and the molten metal solidifies in the range above the midway part. At the time, supply of the molten metal into the cavity by the differential pressure adjusting device is stopped. The casting device having the casting mold according to claim 6.

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