JP2017024050A - Die sand feeding device of core molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a die sand feeding device of a core molding machine in which unevenness and roughness of a core surface due to remaining sand in a blow head can be certainly prevented and endurance of a blow plate can be dramatically raised through simple structural improvement of the blow plate.SOLUTION: A die sand feeding device of a core molding machine comprises a blow plate 1 which includes sand blow ports 3A, 3B mounted at the lower end of a blow head 17, an obstruction plate 5 which is arranged above the sand blow ports 3A, 3B, and a seal material layer 2 which is adhered to the lower surface of the blow plate 1 and surrounds the sand blow ports 3A, 3B. Metal bushes 6A, 6B including a flange part 61 at the upper end are inserted into and engaged with the sand blow ports 3A, 3B, the flange 61 is arranged as protruded upward from the blow plate 1 inner bottom surface, and the periphery of the flange 61 forms a down inclination surface 61a from an upper end opening edge 60 to the inner bottom surface of the blow plate 1.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a mold sand supply device for a core molding machine for modeling a core used for forming a hollow portion of a casting from mold sand.

  In general, for molding cores with complex shapes and constricted parts, dry sand with high fluidity is used as mold sand coated with thermosetting resin (abbreviated as RCS). A shell mold type core molding machine that blows air into the cavities by air pressure is widely used. Also, as this shell mold type core forming machine, from the viewpoint of sand filling property, a top blow method in which mold sand is blown into the mold cavity from above is frequently used (for example, Patent Documents 1 and 2).

  An example of a top blow type shell mold type core molding machine is shown in FIGS. In this shell mold molding machine, the gantry 10 has an inverted L shape composed of a column part 10a and a beam part 10b, the column part 10a side is a mold sand supply part A provided with a mold sand supply hopper 11, and the beam part 10b has a tip side vertically downward. A modeling part B is arranged in which the split mold 20 is arranged. A high pressure air supply device 12 and a pressing air cylinder 13 are installed on the upper part of the modeling part B, and a horizontal guide provided on the beam part 10b. A carriage 15 is fitted to the rail 14 so as to be capable of reciprocating between the mold sand supply part A and the modeling part B via a transfer air cylinder 16. A blow head 17 is suspended from the carriage 15 via vertical guide rods 15a at four corners and a suspension spring 15b. A blow plate 1 is held at the lower end of the blow head 17 by a holding air cylinder 18a. Are attached in an airtight state via four holding arms 18 that open and close.

  In such a core molding machine, when the carriage 15 is located in the mold sand supply part A, a required amount is introduced into the blow head 17 by opening an open / close gate (not shown) below the mold sand supply hopper 11 for a predetermined time. Supply mold sand (slightly larger than the cavity capacity). Next, when the carriage 15 is sent out to the modeling part B, the blow flange 12a of the high-pressure air supply device 12 descends and connects to the upper end opening of the blow head 17, and the blow head 17 is further pushed down and waits downward. In this state, high-pressure air is supplied from the high-pressure air supply device 12 into the blow head 17, and the mold sand in the blow head 17 is blown into the mold 20 by the pressure, and the cavities C 1, C 2 The core of the required shape is formed by binding the mold sand by the heat of the mold 20.

  By the way, in the conventional general blow head 17, as shown in FIGS. 8 and 9, the blow plate 1 is made of aluminum and has a shallow dish shape having a rectangular shape in plan view, and rubber or the like is formed on the lower surface side of the bottom plate portion 1a. A sealing material layer 2 made of an elastomer is adhered, and a sand outlet 3 is formed through the sealing material layer 2 at an important point of the bottom plate portion 1a, and cooling water is provided along the periphery of the bottom plate portion 1a. A passage 4 is formed. And the baffle plate 5 which covers the upper side of the sand outlet 3 is arrange | positioned from the inner bottom face through the attachment bolt 51 and the cylindrical spacer 52, and the mold sand S supplied by this is shown in FIG. The bottom of the baffle plate 5 does not reach the air outlet 3 and accumulates in an inclined angle of repose.

Japanese Utility Model Publication No. 62-46162 (Fig. 6) JP-A-6-7886 (FIGS. 4 and 5)

  However, in the blow head 17 having the conventional structure, the thin sand S1 is thinly present on the inner bottom surface of the blow plate 1 as shown in FIG. In the next core molding, even if the sand S newly supplied into the blow head 17 does not reach the sand outlet 3 by the baffle plate 5, the residual sand S1 around the sand outlet 3 is not air blown. Often fall from the sand outlet 3 and enter the cavities C1 and C2 of the mold 20. The residual sand S1 that has entered the cavities C1 and C2 is immediately cured by the heat of the mold 20, so that when the new sand S blown by high-pressure air is bound, it is integrated. Without falling off from the core surface after modeling, the surface becomes uneven and rough. Therefore, since the core is generally used to form a gas or liquid flow path in a cast product, if there are irregularities or roughness on the surface, it will be transferred to the inner surface of the flow path as it is and the fluid flow will be disturbed. There is a problem that the surface needs to be smoothly corrected with a putty or the like, and the work requires a lot of labor and time, leading to a decrease in production efficiency.

  The aluminum blow plate 1 is advantageous in that it is lightweight and is easy to process the cooling water passage 4 and the like and hardly corrodes. However, as it is repeatedly used, as shown in FIG. 3 is cut by the mold sand S through which the inlet side opening edge 3a passes and wears in a number of grooves, and the seal material layer 2 around the outlet side of the sand outlet 3 is also worn and deformed. While the flow of the mold sand S is disturbed, the filling property to the cavities C1 and C2 is deteriorated and biased, while the interface between the blow plate 1 and the sealing material layer 2 is gradually separated by the blow pressure and finally the seal is broken. In addition, since sand blowing from the interface occurs, there is a problem that a relatively early replacement is required.

  In view of the above-mentioned circumstances, the present invention ensures the unevenness and roughness of the core surface caused by the residual sand in the blow head by a simple structural improvement of the blow plate as a mold sand supply device of the core molding machine. An object of the present invention is to provide an apparatus capable of preventing the blow plate and greatly improving the durability of the blow plate.

  If the means for achieving the above object is shown with reference numerals in the drawings, the mold sand supply device for the core forming machine according to the invention of claim 1 is inserted into the mold 20 from above via the blow head 17. In a core forming machine that fills a mold sand S coated with a thermosetting resin and forms a core by melting and thermosetting the coating layer of the mold sand S, sand outlets 3A and 3B mounted on the lower end of the blow head 17 And a baffle plate 5 disposed above the sand outlets 3A and 3B, and a sealing material layer 2 attached to the lower surface of the blow plate 1 and surrounding the sand outlets A and 3B. The metal bushes 6A and 6B having the flange portion 61 at the upper end are inserted into the sand outlets 3A and 3B, and the flange portion 61 protrudes upward from the inner bottom surface of the blow plate 1. An inclined surface 6 whose outer periphery is descending from the upper end opening edge 60 toward the inner bottom surface of the blow plate 1 It is characterized by forming a a.

  According to a second aspect of the present invention, the projection height h of the flange 61 from the inner bottom surface of the blow plate 1 is set to 3 to 10 mm.

  According to a third aspect of the present invention, the blow sand plate 1 is made of an aluminum material, and the bushes 6A and 6B are made of steel in the core sand supply device of the core forming machine according to the first or second aspect.

  According to a fourth aspect of the present invention, in the mold sand supply device of the core forming machine according to any one of the first to third aspects, the bush 6A is inserted into the sand outlet 3A so as to be movable up and down, and at the lower limit position, the bush The lower end 62 of 6A is set so as to protrude downward from the lower surface of the sealing material layer 2.

  Next, effects of the present invention will be described with reference numerals in the drawings. According to the mold sand supply apparatus of the core forming machine according to the invention of claim 1, the metal bushes 6 </ b> A and 6 </ b> B are provided with the flange 61 at the upper end of the blow plate 1 of the blow head 17 and the blow plate 1. It is inserted in a state of protruding upward from the inner bottom surface, and the outer periphery of the flange portion 61 forms an inclined surface 61a inclined downward from the upper end opening edge 60 to the inner bottom surface of the blow plate 1, so Even if the residual sand S1 exists on the bottom surface, the residual sand S1 enters the sand outlets 3A and 3B by the flanges 61 of the bushes 6A and 6B until the high pressure air is supplied into the blow head 17. With the air blow, the residual sand S1 is sent into the cavities C1 and C2 of the mold 20 through the sand outlets 3A and 3B together with the new mold sand S, and is integrally bonded by the heat of the mold 20 Will do. Therefore, since the residual sand S1 does not come off from the core surface after modeling without causing unevenness and roughness as in the conventional case, a smooth surface core molding product is obtained, so that after molding, High production efficiency can be achieved without the need for correction processing.

  Further, the presence of the bushes 6A and 6B prevents wear of the sealing material layer 2 around the outlet side of the sand outlets 3A and 3B, and blow pressure is applied to the interface between the blow plate 1 and the sealing material layer 2. In addition, sand blowing due to the separation of the interface is prevented, but if the wear on the inlet and outlet sides of the sand outlets 3A and 3B in the bushes 6A and 6B reaches the limit, only the bushes 6A and 6B are new. Therefore, the durability of the blow plate 1 is drastically improved as compared with the prior art. Furthermore, the blow plate 1 is only required to insert the bushes 6A and 6B into the lower holes 30 which are the sand outlets 3A and 3B, and it is not necessary to greatly change the basic structure from the conventional configuration, and the cost is reduced accordingly. There is also an advantage that it can be manufactured.

  According to the invention of claim 2, since the flange 61 of the bushes 6A and 6B is set to a specific protruding height h from the inner bottom surface of the blow plate 1, the remaining sand S1 formed by the previous shaping is sandblasted before air blowing. The entry into the outlets 3A and 3B can be reliably prevented, and the blowing of the mold sand S into the cavities C1 and C2 by air blow can be performed smoothly without any trouble.

  According to the invention of claim 3, since the steel bushes 6A and 6B are extremely hard with respect to the aluminum material of the blow plate 1, the wear on the inlet side and the outlet side of the sand outlets 3A and 3B is correspondingly increased. It is difficult to proceed, and therefore the replacement frequency associated with wear of the bushes 6A and 6B is reduced, and the cost and labor required for maintenance are reduced.

  According to the invention of claim 4, since the lower end 62 of the bush 6A inserted into the sand outlet 3A protrudes downward from the lower surface of the sealing material layer 2, the cavity C1 of the mold 20 is particularly large and deep. In the case of a complicated shape, the distance to the cavity C1 is shortened by the amount of the outlet position of the sand outlet 3A lowered, and the filling property of the mold sand S can be improved, while the bush 6A can be moved up and down to the sand outlet 3A. Even if the pressing position of the blow head 17 and the mold 20 is shifted due to some reason and the lower end of the bush 6A is disengaged from the sand blowing port 21 on the mold 20 side, the mold 20 is inserted. There is no concern that the bush 6A contacting the surface is lifted and the bush 6A is crushed or the mold 20 side is damaged.

An example of the shell mold type | mold core shaping machine to which this invention is applied is shown, (a) is a side view, (b) is a front view. It is a disassembled perspective view of the blow plate of the mold sand supply apparatus which concerns on one Embodiment of this invention. It is the perspective view seen from the lower surface side of the blow plate. The bush used for the blow plate is shown, (a) is a perspective view of the bush having a large inner diameter, (b) is a longitudinal sectional view of the bush, (c) is a perspective view of the bush having a small inner diameter, and (d) is the bush. FIG. It is a vertical side view of the blow plate. It is a vertical front view which shows the state before the air blow in the core shaping | molding by the same type sand supply apparatus. It is a vertical front view which shows the blow head after modeling by the same type sand supply apparatus. It is a vertical front view which shows the state before the air blow in the core shaping | molding by the conventional mold sand supply apparatus. It is a vertical front view which shows the blow head after modeling by the conventional type | mold sand supply apparatus. It is a longitudinal cross-sectional view which shows the abrasion state of the principal part of the blow plate of the conventional type | mold sand supply apparatus.

  Hereinafter, an embodiment of a mold sand supply device for a core forming machine according to the present invention will be described in detail with reference to the drawings. Since this mold sand supply apparatus is applied to the above-described shell mold type core molding machine shown in FIG. 1, description of the entire configuration of the core molding machine is omitted. Further, in the present embodiment, the same reference numerals as those of the conventional configuration are assigned to the components common to the above-described conventional configuration illustrated in FIGS. 8 and 9.

  As shown in FIG. 2 and FIG. 3, the blow plate 1 in this type sand supply device has a shallow dish shape made of aluminum and has a rectangular shape in plan view, similarly to the conventional configuration described above, and on the lower surface side of the bottom plate portion 1a. A sealing material layer 2 made of an elastomer such as rubber is adhered, and a rectangular baffle plate 5 made of aluminum is disposed on the bottom plate portion 1a. 3A and 3B are different from the conventional configuration in that they are configured inside steel bushes 6A and 6B that vertically penetrate the bottom plate portion 1a and the sealing material layer 2.

  As shown in FIG. 2, the baffle plate 5 is screwed into the screw holes 53 of the bottom plate portion 1a through the cylindrical spacers 52 by attaching mounting bolts 51 passed through the bolt insertion holes 5a at the four corners from above. The bottom plate portion 1a is disposed and fixed at a required height so as to leave a sand flow lowering gap g around the periphery. The blow plate 1 has an outward protruding edge portion 1b along both opening edges on the long side, and a cooling water inlet / outlet pipe 7 communicating with the internal cooling water passage 4 protrudes on one short side. Has been.

  As shown in detail in FIGS. 4A to 4D, the bushes 6 </ b> A and 6 </ b> B are cylindrical and have a flange 61 at the tip, and the outer periphery of the flange 61 is inclined downward from the upper end opening edge 60. The inclined surface 61a is formed. Then, as shown in FIG. 5, these bushes 6 </ b> A and 6 </ b> B are inserted from above into the lower hole 30 provided in the bottom plate portion 1 a, and the hook portion 61 is locked to the upper peripheral edge of the lower hole 30. The flange 61 is held in a state protruding upward from the inner bottom surface of the blow plate 1. And the protrusion height h from the blow plate 1 inner bottom face of the collar part 61 is suitably set to the range of 2-10 mm.

  In the case of this blow plate 1, two bushes 6A, 6A having a large inner diameter are arranged close to each other corresponding to the large and deep cavity C1 of the mold 20 shown in FIG. One bush 6B having a small inner diameter is arranged corresponding to the small and shallow cavity C2. 3 and 5, the bush 6A has a lower end 62 protruding downward from the lower surface of the sealing material layer 2, while the lower end 63 of the bush 6B is slightly (usually) lower than the lower surface of the sealing material layer 2. About 0.2 mm) In addition, the downward protrusion amount of the lower end portion 62 of the bush 6A is not particularly limited, and may be a range in which the flange portion 61 does not contact the baffle plate 5 when retracted. The virtual line circle shown in FIG. 3 shows the position and size of the sand blowing port 21 of the cavity C1 during modeling.

  As shown in FIG. 6, in the blow head 17 in which the blow plate 1 having the above-described configuration is attached to the lower end, the mold sand S supplied to the inside does not reach the air outlet 3 below the baffle plate 5 during core molding. It accumulates with the angle of repose angle. When high-pressure air is supplied into the blow head 17, the mold sand S is blown into the sand blowing port 21 of the mold 20 through the sand blowing ports 3 A and 3 B inside the bushes 6 A and 6 B by the pressure. C1 and C2 are filled, and the core of the required shape is formed by binding the sand sand S by the heat of the mold 20. At this time, the flanges 61 of the bushes 6A and 6B protrude from the inner bottom surface of the blow plate 1, but the sand sand S that has received the blow pressure flows into the sand outlets 3A and 3B without any problem as a powder flow. In general, the blow pressure is about 0.4 to 0.5 MPa, and the mold temperature is about 200 to 380 ° C.

  Then, after this modeling is finished, as shown in FIG. 7, thin sand S1 is generated on the inner bottom surface of the blow plate 1, but the flange portions 61 of the bushes 6A and 6B protrude higher than the inner bottom surface of the blow plate 1, and Since the outer periphery of the portion 61 forms an inclined surface 61a having a downward slope from the upper end opening edge 60 to the inner bottom surface of the blow plate 1, even if new mold sand S is supplied to the inside during the next core molding, Until the high pressure air is supplied into the head 17, the brim portion 61 of the bushes 6A and 6B prevents the residual sand S1 from entering the sand outlets 3A and 3B. When the air blow is started, the residual sand S1 is sent together with new mold sand S into the cavities C1 and C2 of the mold 20 through the sand outlets 3A and 3B. The core is formed by binding. Therefore, a part of the residual sand S1 falls into the cavities C1 and C2 before the air blow and is thermally cured as before, and is removed from the core surface after the molding without being integrated with the mold sand S blown by the air blow. As a result, a smooth cored product can be obtained without causing irregularities and roughness, and high production efficiency can be achieved without the need for correction processing after modeling.

  If the upper ends of the flange portions 61 of the bushes 6A and 6B form an annular plane, there is a concern that the residual sand S1 placed on the annular plane may fall into the cavities C1 and C2 before air blowing. However, in these bushes 6A and 6B, the peripheral edge of the upper end of the flange 61 has a sharp shape, and the outer periphery forms an inclined surface 61a having a downward slope so that the residual sand S1 is placed on the flange 61. Therefore, the remaining sand S1 is reliably prevented from falling into the cavities C1 and C2 before the air blow.

  Further, due to the presence of the bushes 6A and 6B, the lower hole 30 of the blow plate 1 corresponding to the sand outlets 3A and 3B is not worn, and the seal material layer 2 around the outlet side of the sand outlets 3A and 3B is also worn. In addition, the blow pressure is not applied to the interface between the blow plate 1 and the sealing material layer 2, and sand blowing due to the separation of the interface is prevented. If the wear on the inlet side and the outlet side of the sand outlets 3A, 3B in the bushes 6A, 6B reaches the limit, only the bushes 6A, 6B need be replaced with new ones. Durability of itself improves dramatically. In particular, as in the embodiment, if the steel bushes 6A and 6B made of extremely high hardness with respect to the aluminum material of the blow plate 1 are used, the wear on the inlet side and the outlet side of the sand outlets 3A and 3B is less likely to progress. Therefore, the replacement frequency accompanying wear of the bushes 6A and 6B is reduced, and the cost and labor required for maintenance are reduced.

  The protruding height h (see FIGS. 5 and 7) of the flange portion 61 from the inner bottom surface of the blow plate 1 is preferably in the range of 2 to 10 mm as described above. The residual sand S1 due to is likely to enter the sand outlets 3A and 3B, and if it is too high, the pressure loss when the mold sand S flows into the sand outlets 3A and 3B by air blow increases. The inclination angle of the inclined surface 61a on the outer periphery of the flange 61 is recommended to be in the range of 30 to 60 °.

  In the embodiment, the lower end 62 of the bush 6A corresponding to the large and deep cavity C1 protrudes downward from the lower surface of the sealing material layer 2, and the outlet position of the sand outlet 3A is lowered to approach the cavity C1. Improves. Further, since the bush 6A is inserted into the sand outlet 3A and can be moved up and down, the pressing position between the blow head 17 and the mold 20 is shifted for some reason, and the lower end of the bush 6A is sand blown on the mold 20 side. Even if it comes off from the mouth 21, the bush 6A contacting the surface of the mold 20 is simply lifted, and there is no concern that the bush 6A is crushed or the mold 20 side is damaged. The bush 6B corresponding to the small and shallow cavity C2 is originally good in filling with the mold sand S, and therefore it is not necessary to project the lower end 63 downward, but from the lower surface of the sealing material layer 2 as in the embodiment. By setting the position slightly indented, it is possible to cope with the thickness reduction accompanying the compression of the sealing material layer 2.

  On the other hand, since the blow plate 1 of this type sand supply device only has the bushes 6A and 6B inserted into the pilot holes 30 serving as the sand outlets 3A and 3B with respect to the conventional configuration, the basic structure from the conventional configuration is obtained. There is also an advantage that it can be manufactured at a low cost without having to be greatly modified.

  In the embodiment, the blow plate 1 corresponding to the mold 20 having the two cavities C1 and C2 having different sizes and shapes is illustrated. However, the blow plate 1 employed in the present invention is the cavity of the mold 20. What is necessary is just to set suitably the number and the diameter and arrangement | positioning of a sand blower outlet which inserts a bush, the length (downward protrusion amount), etc. of a bush according to a number, arrangement | positioning, a shape, and a magnitude | size. Further, the sealing material layer 2 is not limited to the substantially entire lower surface of the blow plate 1 as in the embodiment, and various shapes such as an annular shape surrounding the sand outlets 3A and 3B can be adopted.

  The mold sand supply apparatus of the present invention is not limited to the core molding machine illustrated in FIG. 1, and can be applied to various shell mold core molding machines having different operation mechanisms and forms. For example, for the attachment of the blow plate 1 to the blow head 17, a screwing method at the outward projecting edge portion 1 b can be adopted in addition to the holding method by the holding arm 18 as shown in FIG. 1. Although not shown in the drawings, in the production of the hollow core, the mold before opening the mold is reversed by the vice reversing mechanism, so that the uncured mold sand inside the molded object whose outer surface is cured is discharged by gravity. Thus, the inverted sand removal method for forming the hollow portion or the mandrel method for forming the hollow portion by the structure on the mold side is adopted, but the present invention can be applied to both types of core forming machines.

DESCRIPTION OF SYMBOLS 1 Blow plate 2 Sealing material layer 3A, 3B Sand outlet 5 Baffle plate 6A, 6B Bush 60 Front edge 61 Edge part 61a Inclined surface 62 Lower end part 17 Blow head 20 Mold C1, C2 Cavity

Claims (4)

In a core molding machine that fills a mold sand coated with a thermosetting resin from above through a blow head into a mold, and molds the core by melting and thermosetting the coating layer of the mold sand,
A blow plate having a sand outlet attached to a lower end of the blow head, a baffle plate disposed above the sand outlet, and a sealing material layer attached to a lower surface of the blow plate and surrounding the sand outlet. And
A metal bush having a flange at the upper end is inserted into the sand outlet, and the flange protrudes upward from the inner bottom surface of the blow plate, and the outer periphery of the flange is lower than the upper opening edge. A mold sand supply device for a core forming machine, characterized by forming an inclined surface with a downward slope.   The mold sand supply device of the core forming machine according to claim 1, wherein a protruding height of the flange from the inner bottom surface of the blow plate is set to 2 to 10 mm.   The mold sand supply device for a core forming machine according to claim 1 or 2, wherein the blow plate is made of an aluminum material and the bush is made of steel.   The bush is inserted into the sand outlet so as to be movable up and down, and a lower end portion of the bush is set to protrude downward from a lower surface of the sealing material layer at a lower limit position thereof. A mold sand supply device for a core forming machine according to any one of the above.

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