JP2006035252A - Method and apparatus for making casting mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a sufficiently uniform filling density cannot be achieved by the back squeezing only from above, particularly the problem that the difference of the density between the upper surface portion and the side surface portion of a mold is liable to occur and the required strength is hardly achieved with the increase of the thickness of the sidewall of a casting mold. <P>SOLUTION: The apparatus for making the casting mold comprises a molding sand flask to be filled with molding sand, a fluid containing means which can contain fluid therein and can expand, and a fluid injecting means for injecting the fluid into the fluid containing means. The molding sand flask is filled with the molding sand, and further the fluid containing means is arranged in the molding sand. The molding sand is squeezed by expanding the fluid containing means by injecting the fluid into the fluid containing means by means of the fluid injecting means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mold making method for producing a mold having a uniform filling density and a molding apparatus for carrying out the method.

Conventionally, the thickness of the layer of foundry sand thrown into the casting frame changes according to the unevenness of the model on the model surface plate. When such foundry sand is squeezed with a squeeze head having a uniformly flat end surface, the hardness variation of the mold becomes too large between thick and thin portions of the foundry sand layer. For this measure, a large number of squeeze feet are mounted on the squeeze head, and the squeeze foot corresponding to the inner peripheral wall portion of the casting frame where the casting sand layer is thickened and the central portion where the layer is thinned is divided into a plurality of squeeze feet. Japanese Utility Model Publication No. 6-5001 discloses a mold making apparatus that performs squeeze by changing the driving speed and pressure force of the squeeze foot that has been grouped to make the mold hardness uniform.
Japanese Utility Model Publication No. 6-5001 (page 4, FIG. 1, FIG. 3, page 5, FIG. 4)

  In the above-mentioned conventional device, squeeze is performed by changing the applied pressure etc. with a large number of squeeze feet, but only the back squeeze from above (outside of the foundry sand layer), so the deep position of the foundry sand layer and the shadow of the model The squeeze effect is unlikely to occur up to the place where the sand is difficult to turn. Therefore, a sufficient uniform mold filling density cannot be obtained, and a density difference tends to occur particularly between the upper surface portion and the side surface portion of the model. In addition, since the side wall of the mold formed by the side surface portion of the model becomes thick, there is a problem that degassing failure occurs or a necessary strength is difficult to obtain.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional problems, and by injecting a fluid into a bag member (fluid inclusion means) disposed in the foundry sand, the bag member is inflated to find the foundry sand. By squeezing from the inside of the casting sand layer, it is possible to squeeze perpendicularly to the side surface portion of the model, for example, where the squeeze effect is difficult to occur, and a sufficient uniform mold filling density can be obtained as a whole mold, The present invention provides a molding method and apparatus for a mold which can be formed to a minimum thickness while maintaining a sufficient strength of the mold shell and also has good gas venting.

  In order to solve the above-mentioned problem, the structural features of the invention according to claim 1 are: a foundry sand container filled with foundry sand; a fluid inclusion means capable of enclosing and expanding a fluid; Fluid injection means for injecting fluid into the inclusion means, filling the foundry sand container with the foundry sand and disposing the fluid inclusion means in the foundry sand, and flowing by the fluid injection means Injecting the body into the fluid inclusion means expands the fluid inclusion means to squeeze the foundry sand.

  The structural feature of the invention according to claim 2 is that the casting frame is filled with foundry sand, and is disposed below the casting frame so as to be movable relative to the casting frame up and down, and a model is attached to the upper surface. A model surface plate and a squeeze surface plate mounted on the upper part of the casting frame so as to be relatively close to the model surface plate, and formed by an inner surface of the casting frame and an upper surface of the model surface plate The molded space is filled with foundry sand and is provided on the lower surface of the squeeze surface plate, and includes an expandable and contractible bag member containing the initial shape holding means, and the squeeze surface plate with respect to the model surface plate. The squeeze sand is squeezed by inflating the bag member by injecting the fluid into the bag member by the fluid injection means.

  The structural feature of the invention according to claim 3 is that in claim 2, after the preliminary squeeze and before the bag member is expanded to squeeze the foundry sand, the model surface plate is replaced with the model surface plate. Squeeze the foundry sand from the model platen side by raising the pressure head provided below.

  The structural feature of the invention according to claim 4 is that, in claim 2, the initial shape retaining means is a solid object having a vent hole, and the bag member containing the solid object is press-fitted to the vicinity of the side surface of the model. That is.

  The structural feature of the invention according to claim 5 is that, in the mold making apparatus for forming a mold by squeezing the foundry sand, the foundry sand container filled with the foundry sand and the fluid can be contained and expanded. A fluid inclusion means that is placed in the foundry sand; and a fluid injection means that squeezes the foundry sand by inflating the fluid inclusion means by injecting the fluid into the fluid inclusion means. It is. The fluid inclusion means to be placed in the foundry sand means that when the fluid inclusion means is press-fitted into the foundry sand later or when the foundry sand is supplied later, the fluid injecting means becomes the foundry sand. It includes both cases where it enters the state.

The structural feature of the invention according to claim 6 is that the casting frame is filled with foundry sand, and is disposed below the casting frame so as to be movable relative to the casting frame up and down, and a model is attached to the upper surface. In the mold making apparatus having the model surface plate and the squeeze surface plate mounted on the upper part of the casting frame so as to be relatively close to the model surface plate, provided on the lower surface of the squeeze surface plate, A bag member formed so as to be stretchable, an initial shape holding means for holding the bag member in a fixed shape, and a bag member that is inflated by injecting a fluid into the bag member. And fluid injection means for squeezing sand.

    The structural feature of the invention according to claim 7 is that, in claim 6, the initial shape holding means is a rod-like solid object having a vent hole, and is protruded from the lower surface of the squeeze surface plate.

  According to an eighth aspect of the present invention, in the sixth aspect, the bag member is a mat-like member provided on a lower surface of a squeeze surface plate, and the initial shape holding means includes an elastic member and an on-off valve. A plurality of the elastic members are disposed inside the mat-shaped member, and extend and contract in the thickness direction of the mat-shaped member to hold the lower surface of the mat-shaped member, and the on-off valve is a flow injected into the mat-shaped member. It is to hold the shape of the mat-like member by enclosing the body.

  In the invention according to claim 1 configured as described above, the fluid inclusion means is injected into the fluid inclusion means by the fluid injection means in the foundry sand container filled with foundry sand. Inflate and squeeze the foundry sand. By arranging the fluid inclusion means at a desired position in the foundry sand, squeeze from the inside of the foundry sand where squeezing from the outside of the foundry sand is difficult to produce an effect. A mold can be obtained, and the mold strength can be made uniform. Furthermore, since the fluid spreads the fluid inclusion means with equal pressure, the foundry sand is pressed evenly and it becomes easy to obtain a mold having a uniform filling density.

  In the invention according to claim 2 configured as described above, the bag member press-fitted into the foundry sand to perform the preliminary squeeze expands in the foundry sand by injecting the fluid, It is possible to squeeze the foundry sand at the difficult-to-fill locations and the side portions of the model. Therefore, a sufficient uniform mold filling density can be obtained as a whole, and the mold strength can be made uniform, so that the mold can be formed to a minimum thickness while maintaining a sufficient strength. The removal is also good.

  In the invention according to claim 3 configured as described above, in addition to the effect of the mold making method according to claim 2, a particularly sufficient squeeze can be obtained by squeezing from the model surface plate side (model surface side squeeze). The required strength near the model surface can be obtained. And if this squeeze from the model side (downward), squeeze from the back side (upward), and squeeze from the bag member side (left-right direction) are combined, squeeze from all directions becomes possible as a whole A very high uniform mold filling density can be obtained, and the mold strength can be made uniform.

  In the invention according to claim 4 configured as described above, in addition to the effect of the mold forming method according to claim 2, the bag-shaped member is made of the bag by making the initial shape retaining means a gas-permeable solid material. It is possible to wrap a solid object in close contact with each other, and it is possible to easily press-fit to the vicinity of the side surface of the model in the foundry sand. Thereby, it is possible to squeeze perpendicularly to the side portion of the model that cannot be squeezed perpendicularly to the model surface from the back side or the model platen side.

  In the invention according to claim 5 configured as described above, the fluid inclusion means is injected into the fluid inclusion means by the fluid injection means in the foundry sand container filled with foundry sand. Inflate and squeeze the foundry sand. By arranging the fluid inclusion means at a desired position in the foundry sand, squeeze from the inside of the foundry sand where squeezing from the outside of the foundry sand is difficult to produce an effect. A mold can be obtained, and the mold strength can be made uniform. Furthermore, since the fluid spreads the fluid enclosing means with the same pressure, it is possible to provide a mold making apparatus in which the foundry sand is evenly pressed evenly and a mold having a uniform filling density is easily obtained.

  In the invention according to claim 6 configured as described above, the bag member press-fitted into the foundry sand is inflated at a desired position in the foundry sand by injecting the fluid, and the side surface of the model. It is possible to squeeze the foundry sand in parts and other difficult-to-fill places.

  In the invention according to claim 7 configured as described above, in addition to the effect of the mold making apparatus according to claim 6, the bag shape member is the same by making the initial shape retaining means a gas-permeable rod-like solid. It can be wrapped in close contact with the initial shape holding means, and can be easily press-fitted into the foundry sand to the vicinity of the side surface of the model. Thereby, it can squeeze perpendicularly | vertically with respect to the side surface of a model.

  In the invention according to claim 8 configured as described above, the fluid is injected into the mat-like member from the fluid injection means with the on-off valve opened to form a constant mat shape. At this time, a plurality of elastic members are holding the lower surface of the mat member so that the shape is not biased. When the on-off valve is closed, the fluid is encapsulated in the mat member. Next, the mat-like member is press-fitted into the foundry sand filled in the casting frame by relatively approaching the squeeze surface plate and the model surface plate. The mat-like member is pressed deeply in a place where the layer of foundry sand having a low resistance is thick, and is pressed shallowly in a place where the layer of foundry sand having a large press-fit resistance is thin. Such a thick and thin layer of foundry sand is due to the shape of the model embedded in the foundry sand and the presence or absence of the model. Therefore, in such a deeply or shallowly press-fitted position according to the model shape, etc., by opening the on-off valve and injecting a higher pressure fluid, it is possible to squeeze with a uniform pressure, so that it corresponds to the model shape. Thus, the mold can be formed to have a uniform packing density, and the mold strength can be made uniform.

  A first embodiment of a mold making method and apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view of a mold manufacturing apparatus, FIG. 2 is a partially enlarged view, and FIGS. 3 to 8 are diagrams illustrating a mold manufacturing process.

  In FIG. 1, a pattern carrier 1 having a substantially U-shaped cross section with an open top is moved forward and backward in a vertical molding path direction by a cylinder device 3 as a pressure head. A model surface plate 5 is fixed to the upper surface of the pattern carrier 1, and a model 7 is attached to the upper surface of the model surface plate 5. The model 7 is formed in a substantially cylindrical shape, a step portion having a slightly smaller diameter is formed in the upper portion, and a flange portion is formed in the lower portion.

  A lower frame 9 is fitted on the outer periphery of the model surface plate 5, and a casting frame 11 is superposed on the lower frame 9. The model surface plate 5 is movable up and down relative to the lower frame 9 and the cast frame 11. Above the underlay frame 9 and the casting frame 11, a foundry sand supply device 15 attached to the lower surface of the shuttle 13 and a squeeze surface plate 19 are juxtaposed. When the shuttle 13 is indexed to the squeeze position by the reciprocating cylinder device 10, the squeeze surface plate 19 faces the model surface plate 5, and when the shuttle 13 is indexed to the foundry sand supply position, the foundry sand supply device 15 faces the model surface plate 5. It is like that. These model surface plate 5, casting frame 11 and squeeze surface plate 19 constitute a foundry sand container.

  On the lower surface of the squeeze surface plate 19, a plurality of bar-shaped solid objects 21 as an initial shape holding means are provided in a protruding manner. The rod-like solid material 21 is disposed in consideration of the horizontal position so as to correspond to the side surface of the model 7 when pressed into the foundry sand 17 in a squeeze which will be described later. As shown in FIG. 2, the rod-shaped solid object 21 is formed with, for example, a plurality of ventilation holes 21 b that open to the side surface and the lower end surface of the rod-shaped solid object 21 from an entrance 21 a that is made of wood and provided on the upper end surface. The squeeze surface plate 19 is provided with a vent hole 19a penetrating from the upper surface, and a solid object mounting hole 19b having a diameter slightly larger than the vent hole 19a is provided concentrically below the vent hole 19a. The rod-like solid object 21 is inserted into the fixed object mounting hole 19b at the upper part, and the ventilation hole 19a and the entrance / exit 21a can be continuously ventilated. The length of the rod-shaped solid material 21 is set so as to reach the vicinity of the side surface of the model 7 when pressed into the foundry sand 17.

  The bag member 23 as the fluid enclosing means is made of, for example, a flexible thin rubber (nitrile rubber), and the upper end opening is sandwiched between the mounting hole 19b and the upper flange portion of the rod-shaped solid object 21 and fixed. The lower solid end portion of the bar-like solid object 21 to the attachment portion to the squeeze surface plate 19 is sealed. In a state where a fluid (compressed air) to be described later is not injected, the fluid adheres closely to the surface of the rod-shaped solid material 21 and expands in the peripheral direction when the fluid is injected.

  On the lower surface of the squeeze surface plate 19, a mat-like member 25 as a fluid inclusion means is disposed so as to correspond to the upper surface of the model 7 when squeezing which will be described later. The mat-like member 25 has an engaging portion 25a whose upper end portion and peripheral side wall are made of hard rubber, and a pressing action portion 25b whose entire lower surface can extend and contract. As shown in FIG. 2, the engaging portion 25 a is fitted into a mounting groove 19 d provided on the lower surface of the squeeze surface plate 19, and is sealed by a seal agent (not shown) to connect the squeeze surface plate 19 and the mat-like member 25. The airtightness between them is maintained.

  The squeeze surface plate 19 is provided with a plurality of through holes 19 c that open from the upper surface of the squeeze surface plate 19 into the mat member 25. The mat-like member 25 is in a contracted state on the lower surface of the squeeze surface plate 19 before the fluid injection described later, and expands toward the model 7 when the fluid is injected. .

  A hose 18 is connected to the vent hole 19a and the through hole 19c of the squeeze surface plate 19, and the vent hole 19a and the through hole 19c are connected to a pneumatic pump 20 as fluid injection means through a common pressure passage 18a. Has been. Between the common pressure passage 18a and the pneumatic pump 20, an electromagnetic switching valve 22 is provided as an on-off valve that controls the supply of air.

  Cylinders 16 are vertically provided at the four corners of the squeeze surface plate 19, and a piston 16a is slidably fitted in the cylinder 16 so that the piston rod 16b of the piston 16a protrudes below the bar-shaped solid object 21. The four corners of the casting frame 11 are detachably contacted.

  The cylinder 16 is connected to an end of a pressure hose (not shown), and the other end of the pressure hose is connected to a pressure pump (not shown). An opening / closing valve (not shown) is provided between the cylinder 16 and the atmospheric pressure pump, and the movement of the piston is controlled by opening / closing the opening / closing valve.

  A description will be given of a molding method using the mold making apparatus according to the embodiment together with the operation of the embodiment configured as described above.

  First, a casting frame 11 is placed on a model surface plate 5 fixed on the upper surface of the pattern carrier 1 and an underlaying frame 9 fitted on the model platen 11, and a shuttle 13 is indexed to a foundry sand supply position and quantified. Sand 17 is put into the underlaying frame 9 and the casting frame 11. Subsequently, the shuttle 13 is indexed to the squeeze position, and the squeeze surface plate 19 faces the model surface plate 5.

  At this time, compressed air is supplied from the atmospheric pressure pump through the on-off valve to the cylinders 16 at the four corners of the squeeze surface plate 19, and the piston rod 16b protrudes downward.

  Next, as shown in FIGS. 3, 4 and 9, in this state, the pattern carrier 1 and the model surface plate 5 are raised toward the squeeze surface plate 19 by the cylinder device 3 as a pressure head, and the foundry sand The rod-shaped solid material 21 contained in the bag member 23 is press-fitted into the plate 17. At this time, the tip of the piston rod 16b comes into contact with the four corners of the casting frame 11 and the retraction of the piston rod 16b is restricted, so that the casting rod 11 is pressed into the foundry sand 17 as the rod-like solid material 21 is press-fitted. Regulates floating. Further, as shown in FIG. 10, since the bar-shaped solid material 21 is wrapped in a state of being in close contact with the surface of the bar-shaped solid material 21 by the bag member 23, it can be easily press-fitted into the foundry sand 17. Due to the relative approach of the model surface plate 5 and the squeeze surface plate 19, the casting sand 17 thrown into the casting frame 11 is preliminarily squeezed on the back side by a plurality of rod-shaped solid objects 21.

  Next, as shown in FIGS. 5 and 11, when the cylinder device 3 is further raised, the casting frame 11 and the underlaying frame 9 are restrained from being raised by the piston rod 16 b, and thus retreat relatively. As a result, the foundry sand 17 is squeezed from the model surface plate 5 side (model surface side squeeze), and the squeeze from the squeeze surface plate 19 side (rear side squeeze) is less likely to produce a squeeze effect. Can be focused on, and the mold strength can be made uniform.

  Next, as shown in FIGS. 6 and 12, the pneumatic pump 20 is driven and the electromagnetic switching valve 22 is switched in a direction in which the compressed air 24 flows into the bag member 23 and the mat member 25. The bag member 23 and the mat-like member 25 are explosively expanded by instantaneously injecting the high-pressure compressed air 24 into the bag member 23 and the mat-like member 25. For example, a pressure of 0.5 MPa to 1.0 MPa is applied.

  As shown in FIG. 13, the bag member 23 expands in the circumferential direction and downward of the rod-like solid material 21 and squeezes the foundry sand 17 perpendicularly to the side surface portion of the model 7. This makes it possible to squeeze the vicinity of the side surface of the model 7 that is difficult to squeeze.

  The mat-like member 25 also expands. However, the expanded mat-like member 25 is press-fitted to a deep position when the layer of the foundry sand 17 having a low resistance is thick, and is shallow when the layer of the foundry sand 17 having a large press-fit resistance is thin. Press fit. In FIG. 6, it is shallow in the position with respect to the upper surface of the model 7, and the place where it is not deeply press-fitted. Therefore, squeezing can be performed with a uniform pressure according to such a model shape and the like, so that the mold can be formed with a uniform packing density as a whole corresponding to the model shape. And if this squeeze from the bag member side (left-right direction), squeeze from the model side (downward), and squeeze from the back side (upward) are combined, squeeze from all directions Thus, a very high uniform mold filling density can be obtained as a whole, and the mold strength can be made uniform. The resulting mold can be formed to a minimum thickness while maintaining sufficient strength, and gas venting is also improved.

  Next, as shown in FIGS. 7 and 13, the electromagnetic switching valve 22 is switched in a direction in which air flows out from the bag member 23 and the mat-like member 25, and the pneumatic pump 20 is operated to cause the bag member 23 and the mat-like member 25. Remove the compressed air inside. The bag member 23 and the mat-like member 25 shrink and return to their original dimensions. Therefore, the bag member 23 and the mat-like member 25 generate a gap 27 between them and the wall surface of the foundry sand 17 pressed by the expansion.

  Next, as shown in FIG. 8, when the cylinder device 3 is lowered, the squeeze surface plate 19 is separated from the casting frame 11, and the bar-like solid material 21, the bag member 23, and the mat-like member 25 are formed in the casting frame 11. It is extracted from the mold 29. In this case, the gap 27 can be extracted smoothly. Thus, it is not necessary to consider the draft angle at the time of mold release.

  Next, the vertical movement of the casting frame 11 is restricted by a casting frame support device (not shown), and the cylinder device 3 is further lowered. As a result, the model 7, the model surface plate 5, and the lower frame 9 are separated from the casting frame 11 and the mold 29.

  Next, the casting frame 11 and the mold 29 are conveyed to a pouring station by a roller conveyor (not shown).

Next, a second embodiment will be described with reference to FIGS.

  In FIG. 14, a mat-like member 33 is provided on the lower surface of the squeeze surface plate 31 so as to cover the entire lower surface of the squeeze surface plate 31 from below. The mat member 31 is detachably fixed to the lower surface of the squeeze surface plate 31 by a plurality of fixing plates 35. These fixing plates 35 are fixed to the squeeze surface plate 31 by various attachments such as anchor bolts and rivets. Further, the squeeze surface plate 31 is provided with a plurality of oil passage holes 31 a that open from the upper surface of the squeeze surface plate 31 to the inside of the mat member 33. A plurality of spring members 38 hanging from the lower surface of the squeeze surface plate 31 and holding the lower surface shape of the mat member 33 are suspended inside the mat member 33. A hydraulic hose 37 is connected to each of the oil passage holes 31a of the squeeze surface plate 31, and each of the oil passage holes 31a is connected to a hydraulic pump 39 as a fluid injection means via a common pressure oil passage 37a. . Between the common pressure oil passage 37a and the hydraulic pump 39, an electromagnetic switching valve 41 is provided as an on-off valve that controls the supply of oil.

  As shown in FIG. 14, the mat-like member 33 is supplied with pressure oil 43 as a fluid from the hydraulic pump 39, the electromagnetic switching valve 41 is closed, and the pressure oil 43 is sealed in the mat-like member 33. Thus, the initial shape of the mat-like member 33 is maintained in the balance between the upward lifting force of the spring member 38, the weight of the pressure oil 43 and the mat member 33, and the internal pressure of the pressure oil 43. Yes.

  About another structure, it is the same as that of 1st Embodiment.

  A description will be given of a molding method using the mold making apparatus according to the embodiment, together with the operation of the second embodiment configured as described above.

  First, the hydraulic pump 39 is operated, the electromagnetic switching valve 41 is switched in a direction in which the pressure oil 43 flows into the mat member 33, and the pressure oil 43 flows in a predetermined amount so that the mat member 33 becomes mat.

  Next, as shown in FIG. 14 and FIG. 15, the cylinder device 3 is driven in a state where the electromagnetic switching valve 41 is closed and the pressure oil 43 is sealed in the mat-like member 33, so that the cast frame 11 and the model surface plate are driven. 5. Raise the model 7 and the lower frame 9. The mat-like member 33 is pressed into the foundry sand 17, but is somewhat compressed by the reaction force of the foundry sand 17. Since the resistance is large where the layer of the casting sand 17 is thin, the reaction force of the casting sand 17 is large, and conversely, the reaction force is small where the layer is thick. Therefore, the mat-like member 33 is more strongly compressed as the portion corresponding to the height of the model 7 is higher.

  Next, as shown in FIG. 16, the cylinder device is further raised in the same manner as in the first embodiment. Since the rising of the casting frame 11 and the underlaying frame 9 is restricted by a piston rod (not shown), they are relatively retracted. As a result, the foundry sand 17 is squeezed from the model surface plate 5 side (model surface side squeeze), and the squeeze from the squeeze surface plate 31 side (rear side squeeze) is less likely to cause a squeeze effect. Can be performed intensively, and sufficient mold strength can be obtained.

  Next, as shown in FIG. 17, the hydraulic pump 39 is driven and the electromagnetic switching valve 41 is switched in a direction in which the pressure oil 43 flows into the mat member 33. The mat member 33 is explosively expanded by instantaneously injecting the high pressure oil 43 into the mat member 33. For example, a pressure of 0.5 MPa to 1.0 MPa is applied.

  As shown in FIG. 17, the mat-like member 33 is pressed into the deep position by the pressure of the pressure oil 43 in a place where the casting sand 17 having a low resistance is thick, and in a place where the casting sand 17 layer having a large pressing resistance is thin. It is press-fitted to a shallow position. Thus, since it can squeeze with a uniform pressure according to the model shape arrange | positioned in the foundry sand 17, a casting_mold | template can be shape | molded by the uniform filling density as a whole, and uniform casting_mold | strength can be aimed at.

  And since pressure oil is a liquid and it is hard to compress itself from the compressed air which is gas, a pressure is transmitted directly and it is easy to obtain a strong force in the case of a squeeze.

  The subsequent steps are the same as in the first embodiment.

  Next, a third embodiment for forming the core will be described with reference to FIGS.

  A core-side mold 47 that can be separated from each other is detachably mounted on the core lower mold 45, and the inner wall surface of the core-side mold 47 has a ridge 47 a and a recess that form the outer shape of the core. A groove 47b is provided. A core upper mold 49 is detachably mounted on the upper surface of the core side mold 47, and a rod-shaped solid object 51 as an initial shape holding means protrudes from the lower surface of the core upper mold 49. ing. These core lower mold 45, core side mold 47 and core upper mold 49 constitute a foundry sand container.

  The rod-shaped solid object 51 protruding from the core upper mold 49 is communicated with, for example, a wooden entrance / exit 51a provided on the upper end surface, and a plurality of water holes 51b opened on the side surfaces of the rod-shaped solid object 51 are formed. It is installed. An attachment portion 51c having a small diameter is provided at the upper end of the rod-shaped solid object 51, and the attachment portion 51c is fitted and fixed in an attachment hole 49a formed in the core upper mold 49. One end of a water pressure hose 58 is connected to the inlet / outlet 51 a, and the other end of the hose 58 is connected to a water pressure pump 59. Between the inlet / outlet 51a and the water pressure pump 59, an electromagnetic switching valve 61 is provided as an on-off valve for controlling the supply of the high pressure water 57. A casting sand supply tank 63 is provided above the core upper mold 49, and the core lower mold 45, the core side mold 47, and the core are passed through a supply port 49b formed in the core upper mold 49. The foundry sand 17 is supplied into the space surrounded by the upper mold 49. The foundry sand supply tank 63 is configured to supply the foundry sand 17 as appropriate by a control device (not shown). Other configurations such as the bag member 65 are the same as those in the first embodiment.

  A description will be given of a molding method using the mold making apparatus according to the embodiment, together with the operation of the third embodiment configured as described above.

  First, as shown in FIG. 18, a rod-shaped solid object 51 is arranged in a space surrounded by a core lower mold 45, a core side mold 47 and a core upper mold 49. The water pressure pump 59 is stopped and the electromagnetic switching valve 61 is closed so that the inflow and outflow of the high pressure water 57 is stopped. The foundry sand supply tank 63 is ready to be supplied with the foundry sand 17 in the next step.

  Next, as shown in FIG. 19, the molding sand 17 is surrounded by the core lower mold 45, the core side mold 47 and the core upper mold 49 through the supply port 49 b from the casting sand supply tank 63. Supply in space. The foundry sand 17 is filled in the same space.

  Next, as shown in FIG. 20, the hydraulic pump 59 is driven and the electromagnetic switching valve 61 is switched in a direction in which the high-pressure water 57 flows into the bag member 65. By injecting high-pressure water 57 into the bag member 65 instantaneously, the bag member 65 is expanded explosively. For example, a pressure of 0.5 MPa to 1.0 MPa is applied. Due to the pressure of the high-pressure water 57, the bag member 65 expands to a deep position when the layer of the foundry sand 17 having a low resistance is thick, and expands to a shallow position when the layer of the cast sand 17 having a large press-fit resistance is thin. Accordingly, the squeeze can be performed with an equal pressure according to the shape of the inner wall of the core side mold 47, so that the mold can be formed with a uniform filling density as a whole, and the mold strength can be made uniform.

  Next, as shown in FIG. 21, the electromagnetic switching valve 61 is switched in a direction in which water flows out from the bag member 65, and the water pressure pump 59 is operated to decompress the inside of the bag member 65 to drain water. The bag member 65 contracts and returns to the original size and shape. Therefore, the bag member 65 generates a gap 67 between them and the wall surface of the foundry sand 17 pressed by the expansion.

  Next, as shown in FIG. 22, the core lower mold 45 and the core side mold 47 are separated, and the rod-shaped solid material 51 and the bag member 65 are extracted from the molded core 69. In this case, the gap 67 can be smoothly extracted. In this way, the mold can be released without considering the draft, and the core 69 as shown in FIG. 23 can be obtained.

  Here, since the water used in this embodiment is a liquid and is not easily compressed as compressed air, which is a gas, the pressure is directly transmitted, and a strong force is easily obtained during squeezing. Furthermore, it is easy to handle and can be used at low cost.

  In the above embodiment, air, oil, and water are instantaneously supplied to the bag member and mat-like member, and the bag member and the like are expanded explosively. Alternatively, for example, the supply of the same air or the like may be finely controlled, and high-pressure air or the like may be repeatedly supplied in a wave shape, or may be supplied a plurality of times so as to increase the pressure stepwise.

  The bag member and mat member are made of rubber. However, the present invention is not limited to this, and any film member having airtightness and watertightness may be used. Any device that can be expanded and squeezed by injecting compressed air or the like into a small and folded state can be used.

  Regarding the fluid, in the above embodiment, air, oil, and water are used, but other gases and liquids can also be used.

The figure which looked at the molding apparatus of a casting mold concerning the present invention from the front. The elements on larger scale of FIG. The figure which shows the preparation process of a squeeze. The figure which shows the state which is performing the back side preliminary | backup squeeze. The figure which shows the state which is performing the model surface side squeeze. The figure which shows the state which squeezes by inflating a bag member and a mat-shaped member. The figure which shows the state which shrunk the bag member and the mat-shaped member. The figure which shows a mold release state. The elements on larger scale which show the preparation process of a squeeze. The elements on larger scale which show the state which is performing the back side preliminary | backup squeeze. The elements on larger scale which show the state which is performing the model surface side squeeze. The elements on larger scale which show the state which squeezes by inflating a bag member. The elements on larger scale which show the state which shrunk the bag member. The figure which shows the preparation process of the squeeze of 2nd Embodiment. The figure which shows the state which is performing the back side squeeze. The figure which shows the state which is performing the model surface side squeeze. The figure which shows the state which is expanding the same mat-shaped member and performing squeeze. The figure which shows the preparation process of the squeeze of 3rd Embodiment. The figure which shows the state filled with the foundry sand. The figure which shows the state which expands the bag member and is performing squeeze. The figure which shows the state which contracted the bag member. The figure which shows the same mold release state. The figure which shows the molded core.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 3 ... Cylinder apparatus as a pressure head, 5 ... Model surface plate, 7 ... Model, 11 ... Cast frame, 17 ... Foundry sand, 19, 31 ... Squeeze surface plate, 21 ... Bar-shaped solid material, 23 ... Bag member, 25 , 33 ... mat-like member, 20 ... pneumatic pump as fluid injection means, 38 ... spring member as elastic member, 22, 41, 61 ... electromagnetic switching valve as on-off valve, 39 ... hydraulic pressure as fluid injection means Pump 59: A hydraulic pump as fluid injection means.

Claims (8)

A foundry sand container filled with foundry sand, a fluid inclusion means capable of enclosing and expanding a fluid, and a fluid injection means for injecting the fluid into the fluid inclusion means,
The foundry sand container is filled with foundry sand, the fluid inclusion means is disposed in the foundry sand, and the fluid inclusion means is inflated by injecting the fluid into the fluid inclusion means. A method for forming a mold, characterized in that the casting sand is squeezed. A casting frame filled with foundry sand, a model surface plate disposed below the casting frame so as to be movable relative to the casting frame and mounted with a model on the upper surface, and the model above the casting frame A squeeze surface plate mounted so as to be relatively accessible to the surface plate,
Filling the foundry sand into the space formed by the inner surface of the casting frame and the upper surface of the model surface plate,
The retractable bag member, which is provided on the lower surface of the squeeze surface plate and encloses the initial shape holding means, is brought into contact with the foundry sand by bringing the squeeze surface plate relatively close to the model surface plate. Press-fit and pre-squeeze,
A casting molding method characterized by injecting a fluid into the bag member by a fluid injection means to expand the bag member to squeeze the foundry sand.   3. The method according to claim 2, wherein after the preliminary squeeze and before the bag member is inflated to squeeze the foundry sand, the model surface plate is raised by raising the pressure head provided below the model surface plate. And squeezing the foundry sand from the side of the model surface plate.   3. The mold making method according to claim 2, wherein the initial shape holding means is a solid object having a vent hole, and a bag member containing the solid object is press-fitted to the vicinity of the side surface of the model. In a mold making device that molds a mold by squeezing foundry sand,
A foundry sand container filled with foundry sand;
Fluid enclosing means capable of enclosing and inflating a fluid and being placed in foundry sand;
A mold making apparatus comprising fluid injection means for inflating the fluid inclusion means by squeezing the foundry sand by injecting the fluid into the fluid inclusion means. A casting frame filled with foundry sand, a model surface plate disposed below the casting frame so as to be movable relative to the casting frame and mounted with a model on the upper surface, and the model above the casting frame In a mold making apparatus having a squeeze surface plate mounted relatively close to the surface plate,
A bag member provided on the lower surface of the squeeze surface plate and formed to be stretchable;
Initial shape holding means included in the bag member and holding the bag member in a certain shape;
A mold making apparatus comprising fluid injection means for inflating the bag member by injecting the fluid into the bag member to squeeze the foundry sand.   7. The mold making apparatus according to claim 6, wherein the initial shape holding means is a rod-like solid object having a ventilation hole, and is protruded from the lower surface of the squeeze surface plate.   7. The bag member according to claim 6, wherein the bag member is a mat-like member, the initial shape holding means includes an elastic member and an opening / closing valve, and a plurality of the elastic members are disposed inside the mat-like member. A mold making apparatus characterized by holding the lower surface of the mat-shaped member by expanding and contracting in the thickness direction, and the on-off valve enclosing a fluid injected into the mat-shaped member to maintain the shape of the mat-shaped member .

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