JP6268571B2 - Casting apparatus and casting article manufacturing method - Google Patents

Description

  The present invention relates to a casting apparatus for obtaining a desired article using a breathable mold.

  For the production of cast articles in gravity pouring, a mold formed using sand particles, which is a breathable mold, that is, a so-called sand mold is most commonly used. When such a breathable mold is used, when the molten metal is filled into the cavity having a specific shape, the remaining gas (generally air) is pushed out from the surface of the cavity, and the molten metal is applied to the entire cavity. (Hereinafter, also referred to as a molten metal), and a casting that is substantially the same as the cavity can be obtained. The mold cavity generally has a sprue part, a runner part, a feeder part, and a product part, and the molten metal is supplied in this order. In the conventional technique, the molten metal head height sufficient to fill the product portion is formed in the gate portion, and pouring is completed.

  When the cast article solidified in this way is seen, the gate part, runner part, feeder part and product part are connected as a casting. Here, the hot water part is a cavity set for the health of the product and it can not be said that it is an unnecessary part. It is an unnecessary part. Therefore, the injection yield cannot be significantly improved as long as the molten metal is solidified in the gate or runner. In addition, if the casting is formed by connecting unnecessary parts, a considerable man-hour is required for sorting the product part and the unnecessary part in the separation process of the product part, which is a subsequent process, and the production efficiency is lowered. Therefore, in gravity pouring, the presence of a sprue part or a runner part as a casting has been a big problem.

  By the way, recently, epoch-making techniques for the above problems have been proposed in Patent Document 1 and Patent Document 2. The technique is to fill the desired cavity portion, which is a part of the cavity of the gas-permeable mold, with the molten metal, so that it is smaller than the entire volume of the mold cavity and is almost equal to the desired cavity portion. Gravity pouring the molten metal of a volume, and before the molten metal is filled into the desired cavity, compressed gas is sent from the sprue to fill the desired cavity with the molten metal and solidify it. Is. According to this method, the pressure required depending on the height of the molten metal head is compensated by the compressed gas, so that it is expected that the molten metal in the runner section as well as the sprue section can be almost unnecessary. Yes.

JP 2007-75862 A JP 2010-269345 A

  The present inventors have studied to realize the methods described in Patent Document 1 and Patent Document 2. As a result, in this method, since it is essential to switch from the gravity pouring stage to the gas supply stage, the molten metal introduced into the product section stagnates at the timing of this switching, and the hot water boundary and illumination etc. Recognized that there is a possibility of generating defects. In order to solve such a problem in the stagnation of the molten metal, a casting apparatus capable of performing the switching as quickly as possible is necessary so as not to cause the stagnation of the molten metal in the product portion as much as possible.

  In view of the above problems, an object of the present invention is to provide a casting apparatus capable of quickly switching from a gravity pouring stage to a gas supply stage.

  The inventors of the present invention solve the above-mentioned problem by evacuating the pouring device for pouring molten metal into the pouring gate portion from the operating space of the gas supply device at least before the end of pouring. We have found out that we can do it and have reached the present invention.

That is, the present invention is a casting apparatus for obtaining a cast article by gravity pouring a molten metal into a breathable mold, the breathable mold having a gate portion, a runner portion and a product portion in the mold, and the gate portion A pouring device for pouring the molten metal into the gas inlet and a gas air supply device arranged to be connectable to the pouring gate after pouring, and the pouring gate portion serves as a flow path to the runner And a spout cup portion whose diameter is larger than that of the introduction pipe portion that receives the molten metal that has flowed down from the pouring device, and the pouring device, in the initial stage of pouring, In the latter part of pouring, the molten metal stream line is moved to a position within the pouring cup part and away from the vicinity of the inlet pipe part, at least in the pouring stage. Evacuate from the operating space of the gas supply device before the end and after pouring Connect the gas insufflation apparatus sprue, pushing the molten metal insufflation gas from the gas the gas supply apparatus, a casting apparatus, characterized in that it is intended to fill the molten metal in the product section.

In the present invention, the gate cup part preferably has a shape in which an opening formed in the introduction pipe part extends in one direction away from the introduction pipe part. The gate cup part may be formed so as to become gradually shallower in a direction away from the introduction pipe part. Moreover, it shall be formed in the shape where two bowl-shaped hollows were connected.

Other forms of the present invention include a product part as a mold cavity, a runner part that forms a molten metal flow path to the product part, an introduction pipe part that is a flow path to the runner part, and the introduction pipe part. The molten metal is poured into the mold cavity by gravity, and then the molten metal is pushed into the mold cavity by pushing the molten metal into the mold cavity. In the manufacturing method of a casting article in which the molten metal is filled in a portion, in the initial stage of the pouring, the stream line of the molten metal is positioned in the vicinity immediately above the introduction pipe portion, and in the latter stage of the pouring, the A flow line of the molten metal is within the range of the pouring cup portion and is separated from the vicinity immediately above the introduction pipe portion, and a gas gas feeding device for feeding the gas before the pouring is completed is connected to the pouring gate portion. And a method for producing a cast article in which the gas is supplied.

  According to the present invention, it is possible to quickly connect the gas air supply device to the gate after pouring. As a result, it is possible to suppress the occurrence of defects such as the hot water boundary and illumination due to the stagnation of the molten metal.

It is a figure which shows an example of operation | movement of the casting apparatus of this invention. It is a figure which shows an example of the gate cup part which concerns on this invention. It is a figure which shows another example of the gate cup part which concerns on this invention. It is a figure which shows another example of the gate cup part which concerns on this invention. It is a figure which shows an example of the connection to the gate part of the gas supply apparatus which concerns on this invention.

  In conventional casting by gravity pouring, the amount of molten metal required to fill the product part is supplied from the pouring part only by gravity during pouring, so the problem of stagnation of molten metal does not cause abnormalities in the casting equipment, etc. As long as it does not occur.

  On the other hand, in the casting accompanied by the transition from the gravity pouring stage to the gas supply stage as proposed in Patent Document 1 and Patent Document 2, the driving force for filling the product portion with the molten metal is switched halfway. It will be. Therefore, at the timing of switching, it is necessary that the molten metal is not stagnated at all, or even if the molten metal is stagnated, a very short time that does not affect the quality is required.

  As one of the factors that hinder the speeding up of the switching from the gravity pouring stage to the gas air feeding stage, the present inventor has a pouring device such as a ladle in a conventional casting apparatus that has a molten metal as close to the top of the sprue as possible. As a result of being adjusted so as to flow down, it has been found that the gas supply device cannot be connected to the gate portion unless the pouring device is retracted after pouring.

  Therefore, in the present invention, the pouring device employs a device configuration that retreats from the operating space of the gas supply device at least before the end of pouring. Hereafter, the principal part of this invention is demonstrated in detail.

  First, in the present invention, the gate part has an introduction pipe part that becomes a flow path to the runner and a spout cup part that has a diameter larger than that of the introduction pipe part that receives the molten metal flowing down from the pouring device. Shall. By having the spout cup portion expanded in diameter as described above, the molten metal can be continuously received until the end of pouring even when the pouring device is retracted from the operation space of the gas supply device.

  In the present invention, at least before the end of pouring, the pouring device only has to be withdrawn from the operating space of the gas supply device, and the molten metal is allowed to flow down to a position separated from the position immediately above the pouring gate from the beginning of pouring. It is good also as what is received in the diameter spout cup part. However, with this configuration, the entire amount of the molten metal always comes into contact with the inner peripheral surface of the spout cup, which is disadvantageous in terms of mold damage, entrainment of air, and oxidation of the molten metal.

  On the other hand, in the initial stage of pouring, the stream line of the molten metal is positioned in the vicinity immediately above the introduction pipe part, and in the latter part of the pouring process, the stream line of the molten metal is within the range of the pouring cup, and the introduction pipe part If it is moved to a position away from the immediate vicinity, the occurrence of the above problem can be suppressed.

  As a specific pouring device in the present invention, a ladle, a pouring pipe, a pouring bath and other pouring means can be applied. In retreating, a method of moving the pouring device in one direction away from the introduction pipe portion (perpendicular to the axis of the introduction pipe portion) is preferable because it is simple.

  Moreover, in this invention, the space which a pouring apparatus can evacuate becomes large, so that the diameter expansion part of a gate cup is large. However, as described above, since the pouring device is the simplest device that can be retracted in one direction, the pouring cup portion has one direction (introduction) in which the opening formed in the introduction pipe portion is separated from the introduction pipe portion. A shape extending in a direction perpendicular to the axis of the tube portion is preferable.

  Further, in the present invention, the enlarged diameter portion in the gate cup portion means a frontage portion wider than the introduction pipe portion, and has a bowl shape, a cone shape, a pyramid shape, a truncated cone shape, a truncated pyramid shape, etc. It may be.

  Note that the gate cup portion is usually formed by using a gate cutter that rotates a base material having a U-shaped edge surface on a flat plate to cut a mold. When such a gate cutter is used, it can be formed into a bowl shape, a cone shape, or a shape in which they are stretched. At this time, after forming a cup-shaped depression on the introduction pipe section, the cup gate is moved in one direction away from the introduction pipe section to form a shape in which two bowl-shaped depressions are connected. Can do. Further, the gate cup portion may be formed so as to become gradually shallower in a direction away from the introduction pipe portion. By forming in this way, the stay of the molten metal in the gate cup part can be further reduced.

  In the present invention, after the pouring is completed, the gas insufflator is connected to the spout, the gas is infused from the gas insufflator, the molten metal is pushed in, and the product is filled with the molten metal.

  In the present invention, as described above, since the pouring device is retracted from the operation space of the gas gas supply device at least before the end of pouring, the gas gas supply device is immediately connected to the gate portion. , Can do air.

  In this invention, it is preferable that the connection part with the gate part in a gas air supply apparatus shall be nozzle shape. By making it into a nozzle shape, there is an advantage that it is possible to make a connection that quickly and hardly leaks air by fitting the nozzle into the gate, in other words, by inserting. Further, it is preferable to form a tapered side surface as the nozzle because it is easy to fit. Further, if a tapered wall surface is formed at the gate, the nozzle and the gate can be securely fitted together.

  Further, the type of gas applied to the present invention is not particularly limited, but air may be used from the viewpoint of cost, and non-oxidizing gas such as argon, nitrogen or carbon dioxide from the viewpoint of preventing oxidation of the molten metal. May be used. Further, in addition to the gas, a cooling medium such as a mist for promoting cooling may be supplied, or a solid material such as refractory particles as shown in Patent Document 2 may be supplied to block the runner.

  Hereinafter, a mold which is a basic requirement of the present invention will be described. The present invention is a casting device that obtains a cast article by gravity pouring a molten metal into a gas-permeable mold, and has a gate part, a runner part, a product part, and, if necessary, a feeder part in the mold. Applies to breathable molds.

  The breathable mold is generally a sand mold, shell mold, self-hardening mold or other mold formed using sand particles, but a mold formed using ceramic particles or metal particles can also be applied. Further, even a mold that is hardly air permeable such as plaster can be used as a gas permeable mold by mixing a gas permeable material or by partially providing a gas permeable material with sufficient gas permeability. Further, even a mold using a material having no air permeability such as a metal mold can be used as a gas permeable mold when other air holes such as a vent hole are provided to provide air permeability.

(Embodiment 1)
Next, the casting apparatus according to Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an example of the operation of the casting apparatus of the present invention. Specifically, FIG. 1 is a schematic diagram illustrating a process of gravity pouring a molten metal using a casting apparatus according to Embodiment 1 of the present invention, feeding gas, and filling a molten metal into a product part. is there. In FIG. 1, the aspect of the gas supply nozzle 1a which constitutes a part of the gas gas supply device 1 in the present invention is a case where a gas supply nozzle having a straight side surface, that is, a side surface without a taper is used. The mode of the pouring device is a ladle 2, and the mode of the spout cup portion 5a in the present invention is a bowl-like shape expanded from the central axis of the introduction pipe portion 5b. It is not limited to these.

  The casting_mold | template 3 is shown as an example which uses the fresh sand type | mold which is a breathable casting_mold | template. The mold 3 is matched with the upper frame 3a and the lower frame 3b and placed on the surface plate 3c. The mold cavity 4 is composed of a gate portion 5 composed of a gate portion 5a and an introduction pipe portion 5b that form a molten metal flow path, a runner portion 6, a feeder portion 7, and a product portion 8. Moreover, although the feeder part 7 may not be provided, in Embodiment 1 demonstrated in FIG. 1, the desired cavity 9 is shown as an example comprised by the product part 8 and the feeder part 7. FIG.

  FIG. 1A is an initial stage of pouring. A part of the ladle 2 is in the range of the operation space 10 of the air supply nozzle indicated by a region surrounded by a two-dot chain line. After the molten metal 11 flows down from the ladle 2 to the inner wall of the spout cup portion 5a while forming the flow line 13a, the molten metal 11 is introduced into the product portion 8 through the introduction pipe portion 5b, the runner portion 6, and the feeder portion 7. This indicates the state.

  Next, FIG. 1 (b) is a later stage of pouring, and the ladle 2 moves to form a stream line 13b from the ladle 2 and is poured into the pouring gate 5 while the ladle 2 moves to Retracting out of the range of the operation space 10, the air supply nozzle 1a is shown moving to the position immediately above the gate 5 (in the case of FIG. 1B, directly above the introduction pipe 5b).

  Next, FIG. 1 (c) shows a state in which the air supply nozzle 1 a is lowered toward the gate 5 and connected (in this case, fitted to the introduction pipe 5 b) immediately after the end of gravity pouring.

  In FIG. 1D, after the state of FIG. 1C, before the molten metal 11 starts to solidify, the gas 12 indicated by a plurality of arrow lines passes from the air supply device 1 through the air supply nozzle 1a. A state is shown in which the molten metal 11 is filled in a desired cavity 9 due to the gas 12 being fed into the runner 6 after being fed into the gate 5 and the gas 12 being fed.

  Thus, the gas pouring device 1 can be quickly connected to the pouring gate 5 by retracting the pouring device 2 from the operating space 10 of the air feeding nozzle before the end of pouring.

  In this aspect, in the initial stage of pouring, as shown in FIG. 1 (a), the streamline 13a is positioned in the vicinity immediately above the introduction pipe portion 5b, thereby suppressing the scattering of the molten metal on the inner wall of the spout cup portion 5a. In addition, the molten metal 11 can flow down to the introduction pipe portion 5b efficiently and in a short time. In the latter stage of pouring, as shown in FIG. 1 (b), the streamline 13b is moved to a position within the range of the pouring cup portion 5a and away from the vicinity immediately above the introduction pipe portion 5b. The air nozzle 1a can be moved right above the introduction pipe portion 5b without being exposed to the molten metal in the gravity pouring.

(Embodiment 2)
FIG. 2 shows an example in which the shape of the pouring cup portion 5a of the pouring device shown in FIG. 1 is changed, and the opening formed in the introducing pipe portion 5b of the pouring cup portion 5c is separated from the introducing pipe portion 5b. The example which formed in the shape extended in one direction A shown by the arrow line is shown. 2 is an enlarged view of the vicinity of the gate cup portion 5c, FIG. 2 (a) is a plan view from above the mold 3, and FIG. 2 (b) is a cross-sectional view.

  In the latter half of the pouring, it is quick and efficient that the ladle 2 is separated by an operation in one specific direction perpendicular to the central axis of the introduction pipe portion 5b. For this reason, the opening formed in the introduction pipe portion 5b is formed by the ladle 2 rather than having a bowl-like shape symmetrical to the central axis of the introduction pipe portion 5b as in the pouring cup portion 5a shown in FIG. It is more reasonable to make the shape like a gate cup portion 5c extending in one direction A away from the introduction pipe portion 5b. The length extending in one direction A of the pouring cup portion 5c is preferably set to such a length that the molten metal flow line 13b in the latter half of pouring can be sufficiently accommodated within the range of the pouring cup portion.

(Embodiment 3)
FIG. 3 shows another example in which the shape of the pouring cup portion 5a of the pouring device shown in FIG. 1 is changed, and the opening formed in the introducing pipe portion 5b of the pouring cup portion 5d is an introducing pipe portion 5b. An example is shown in which the shape extends in one direction A and is formed in a shape in which two bowl-shaped depressions 14a and 14b are connected. 3 is an enlarged view of the vicinity of the gate cup portion 5d, FIG. 3 (a) is a plan view from above the mold 3, and FIG. 3 (b) is a cross-sectional view.

By adopting the shape of the pouring cup portion 5d , it is easy to fit the molten metal stream line 13b in the latter stage of pouring within the range of the pouring cup portion, and the scattering of the molten metal outside the pouring gate can be suppressed. Further, the shape of the gate cup portion 5d is such that the gate cutter for forming the bowl-shaped depression 14a is moved to the position of the bowl-shaped depression 14b in one direction A away from the introduction pipe section and the mold 3 is deleted. Since it can form easily, the increase in time required for formation of a gate part can be suppressed.

(Embodiment 4)
FIG. 4 shows another example in which the shape of the gate cup portion 5a of the pouring device shown in FIG. 1 is changed. FIG. 4 shows a shape in which the opening formed in the introduction pipe part 5b of the spout cup part 5e extends in one direction A away from the introduction pipe part 5b, as in FIG. Although the shape of 14b is connected, the sprue cup portion does not have a horizontal bottom as shown in FIG. 3, but is formed so as to gradually become shallower in a direction away from the introduction pipe portion. 4 is an enlarged view of the vicinity of the gate cup portion 5e, FIG. 4 (a) is a plan view from above the mold 3, and FIG. 4 (b) is a cross-sectional view.

  The shape of the gate cup portion 5e is preferable because there is an effect that the molten metal flows down efficiently to the introduction pipe portion 5b. Further, the shape of the gate cup portion 5e can be easily obtained by moving the gate cutter forming the bowl-shaped depression 14a to the position of the bowl-shaped depression 14b in one direction A with the upper inclination angle and deleting the mold 3. Can be formed.

(Embodiment 5)
FIG. 5 is a view showing an example of the connection of the gas supply device to the gate portion in the pouring device shown in FIG. 1, and the gate portion is an example having the shape of the gate portion 5d shown in FIG. It is shown.

  FIG. 5 shows a state in which, after the end of gravity pouring, the air supply nozzle 1b in which the tapered wall surface 15 is formed in the vicinity of the tip is fitted to the introduction pipe portion 5f having the same tapered surface. By adopting such a shape of the air supply nozzle and the shape of the introduction pipe portion, alignment with the introduction pipe portion can be performed more easily, so the period from the completion of gravity pouring until the start of gas supply is increased. Further shortening is possible.

DESCRIPTION OF SYMBOLS 1 Gas air supply apparatus 1a Air supply nozzle 1b Air supply nozzle 2 Ladle 3 Mold 3a Upper frame 3b Lower frame 3c Surface plate 4 Mold cavity 5 Pouring part 5a Pouring cup part 5b Introducing pipe part 5c Pouring cup part 5d Pouring cup part 5e Spout cup part 5f Introducing pipe part 6 Runner part 7 Presser part 8 Product part 9 Desired cavity 10 Operating space of air supply nozzle 11 Molten metal 12 Gas 13a Stream line 13b Stream line 14a Bowl-shaped depression 14b Bowl-shaped depression 15 Tapered wall surface A One direction away from the inlet tube

Claims (4)

A casting apparatus for obtaining a cast article by gravity pouring a molten metal into a breathable mold, a breathable mold having a pouring part, a runner part and a product part in the mold, and pouring the molten metal into the pouring part. A pouring device, and a gas air supply device disposed so as to be connectable to the pouring gate after pouring, the pouring gate portion being an introduction pipe portion serving as a flow path to the runner, and the pouring water A pouring cup portion whose diameter is larger than that of the introduction pipe portion for receiving the molten metal flowing down from the apparatus, and the pouring apparatus has a stream line of the molten metal immediately above the introduction pipe portion in the initial stage of pouring. In the latter part of pouring, by moving the stream line of the molten metal to a position within the pouring cup part and away from the vicinity immediately above the introduction pipe part, at least before the end of pouring Evacuate from the operating space of the gas supply device, and after pouring, the gas supply device is Connected to parts, push the molten metal insufflation gas from the gas the gas supply apparatus, a casting apparatus, characterized in that it is intended to fill the molten metal in the product section. The sprue cup portion, the casting apparatus according to claim 1 in which the opening formed in the inlet pipe portion, characterized in that it is a shape extending in one direction away from the inlet pipe portion. The casting apparatus according to claim 1 or 2 , wherein the gate cup portion is formed in a shape in which two bowl-shaped depressions are connected. Product part as mold cavity, runner part forming molten metal flow path to the product part, introduction pipe part which is a flow path to the runner part, and a spout cup part whose diameter is larger than that of the introduction pipe part A casting in which a molten metal is gravity poured into the pouring part of a breathable mold having a pouring part, and then gas is fed into the mold cavity to push the molten metal, and the product part is filled with the molten metal. A method for manufacturing an article, comprising:
In the initial stage of the pouring, the molten metal streamline is positioned in the vicinity immediately above the introduction pipe portion, and in the later stage of the pouring, the molten metal streamline is within the range of the pouring cup portion and the introduction is performed. A cast article characterized in that it is separated from the vicinity immediately above the pipe portion and a gas air supply device for supplying the gas before the pouring ends is connected to the gate portion to supply the gas. Production method.

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