JP6135574B2 - Casting mold making equipment - Google Patents

Description

The present invention relates to a casting mold making apparatus .

  In general, molding of a mold (main mold or core) is performed in the order of manufacturing a model, forming a mold using the model, and removing the mold. With respect to this molding technique, Patent Document 1 discloses that in core molding by the cold box method, core sand is filled into the core mold, and then the core is molded by blowing amine gas, and then the mold is opened. It describes that the core is removed by an extrusion pin. This document further describes that compressed air is ejected from a slit opened on the side surface of the extrusion pin at the time of die cutting to blow away sand and resin particles adhering to the periphery of the extrusion pin.

JP-A-61-159244

  In the case of the above-described cold box method, sand is bonded with resin by blowing amine gas, so that the obtained mold has high bending strength and crushing strength. For this reason, even if the mold is removed by the extrusion pin, the mold is hardly damaged.

  In contrast, the present invention is premised on molding a mold with green sand. In the molding of a mold using green sand, the mold (model) is lowered while the casting frame is received by a leveling cylinder or the like, whereby the casting mold is removed from the casting mold to the casting frame side.

  However, a mold molded from green sand is lower in strength and hardness than a mold using an organic binder (resin) such as a cold box method. For this reason, the mold is easily broken by the die-cutting resistance of the mold and is easily divided into the mold side and the casting mold. On the other hand, it is conceivable to assist the die extraction with an extrusion pin. However, in the case of green sand, since the strength and hardness of the mold is low, a depression is formed in the contact portion of the extrusion pin of the mold, and the mold is There is a problem of collapse.

  In particular, in the molding of a mold for forming a cylindrical casting, the model becomes a cylindrical shape, and in order to prevent a reduction in arrangement efficiency and an increase in machining allowance, the draft angle cannot be increased, and the die resistance is reduced. growing. As a result, the mold is easily broken at the upper end of the cylindrical model.

  Therefore, the present invention prevents the mold made of green sand from being damaged when the mold is removed.

  In order to solve the above-described problems, the present invention assists the mold removal with air.

The mold making device that forms the cylindrical casting presented here is
A mold in which a plurality of cylindrical models are erected on a model support base at intervals; a casting frame set in the mold; a green sand feeding means for feeding green sand into the casting frame; and And a squeeze device that molds the green sand in the casting mold and molds the mold,
On the outer peripheral surface of the cylindrical model, a number of ridges extending in the drawing direction are formed at intervals in the circumferential direction,
At the bottom of the cylindrical model, an air outlet for applying air pressure from the bottom to the mold at the time of mold opening opens,
The model support base is provided with a plurality of columnar guide members that form guide holes extending in the mold drawing direction in the mold, and the escape slope of the guide member is made smaller than the escape slope of the cylindrical model, or The guide member has a draft gradient of zero .

According to this molding apparatus , the mold receives a force in the mold drawing direction by the air pressure applied to the mold from the bottom of the cylindrical model at the time of mold drawing. In this case, unlike an extrusion pin that locally presses a part of the mold, air pressure is applied to the entire lower surface of the mold columnar part in the cylindrical model. In addition, since air rises while passing through the sand grains of the mold columnar part, the mold columnar part not only receives air pressure on the lower surface thereof, but also the force caused by air flow (the air rising inside the mold column) It also receives the force that hits the sand grains and pushes upward. That is, the entire mold columnar portion receives a propulsive force in the mold drawing direction. Further, the air flows between the inner surface of the cylindrical model and the mold columnar portion, thereby reducing the punching resistance. Thus, the cutting die becomes smooth, it has difficulty lead to rupture or collapse of the mold.

As above mentioned, since the mold obtained by the green mold sand is low strength and hardness, even if the smoothly cutting die itself by the air assist, the relative positions of the mold and the mold is deflected in the direction perpendicular to the cutting die direction during cutting die There is a concern that the mold may be damaged by the collision with the model. In particular, there is a problem that when the mold is advanced and a gap is formed between the mold and the cylindrical model, the mold sways against the mold.

  Therefore, a guide member is provided in the mold so that a guide hole is formed in the mold by the guide member. Even when the mold is removed and the gap is generated, there is almost no gap between the guide member and the guide hole. Or it was made not to occur substantially. Therefore, the lateral movement of the mold is prevented by the guide member, so that the mold can be prevented from being broken. In this case, the draft of the guide member is made smaller than the draft of the cylindrical model, or the draft of the guide member is made zero, so that this guide member works effectively as a guide for the die. The guide member is preferably the same length as the cylindrical model or longer than the cylindrical model.

A preferred aspect of the invention relating to the molding apparatus is characterized in that a vent hole is formed around the cylindrical model of the model support base for extracting air when the green sand is solidified to mold a mold. . Accordingly , air can be discharged from the periphery of the cylindrical model to the lower side of the mold when the green sand is squeezed , and molding of the mold by squeezing becomes easy.

According to the present invention, a large number of ridges extending in the mold drawing direction are removed from the bottom of a cylindrical model formed on the outer peripheral surface at intervals in the circumferential direction while applying air pressure to the mold, and the model support The base is provided with a plurality of columnar guide members that form guide holes extending in the mold drawing direction in the mold, and the guide member has a drop gradient smaller than that of the cylindrical model, or the guide member is removed. since the slope was zero, the overall casting mold columnar portion of the cylindrical inner model can give cutting die force, moreover, it is possible to reduce the cutting die resistance by air, further, the lateral shake of the mold at the time of cutting dies since Ru is prevented by the guide member, it is easy to cutting die without breaking the mold with live type sand.

The front view of a mold making apparatus. The perspective view of a metal mold | die. The top view of a cylindrical model. The top view of a metal mold | die. The perspective view which shows a cylindrical model bottom part. The front view which shows a mold release agent coating device. The front view of the mold making apparatus in the state which poured green sand into the metal mold | die. The front view of the mold making apparatus at the time of a squeeze. The front view of the mold making apparatus at the time of die-cutting. Sectional drawing which shows a die-out air assist state.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the invention, its application, or its use.

  The present embodiment relates to a mold making method and apparatus for molding an engine cylinder liner as a cylindrical casting. For molding the mold, green sand (casting sand using silica sand as an aggregate and clay (bentonite) as a binder) is used.

(Mold molding equipment)
In FIG. 1, 1 is a lower mold for forming a lower mold for forming a cylinder liner, and 2 is an upper mold for forming an upper mold (runner or the like) for forming a cylinder liner. The lower mold 1 is provided with a plurality of cylinder liner models (hereinafter referred to as “liner models”) 3. The dies 1 and 2 are held side by side on the bolster 4. The bolster 4 is supported by a lift table 5, and the lift table 5 is moved up and down by a frame set cylinder 6. The molds 1 and 2 are transported onto the lift table 5 of the molding station by the transport means while being set in the bolster 4 in advance, and are held on the lift table 5.

  Above the bolster 4, there is provided a casting frame conveying device 11 that sequentially conveys the lower mold casting frame 7 and the upper mold casting frame 8 by rollers 9 and is positioned on the bolster 4. A lower mold filling frame 12 placed on the casting frame 7 and an upper mold filling frame 13 placed on the casting frame 8 are supported by the frame 14 above the casting frame conveying device 11. The fill frame 14 is received by a frame receiver 15. Further, the casting frame transport device 11 is provided with a leveling cylinder 16 that receives and supports the four corners of the casting frames 7 and 8 when the casting frame descends as will be described later.

  Above the filling frame 14, a squeeze head 19 having a lower squeeze board 17 and an upper squeeze board 18 that are moved up and down by squeeze cylinders (not shown), and a lower louver as green sand input means. The hobber 21 and the upper mold louver hopper 22 are provided side by side in a direction orthogonal to the casting frame conveying direction. The squeeze head 19 and the louver hoppers 21 and 22 are integrally moved forward and backward in the orthogonal direction by a shuttle device (not shown), and each of them is selectively positioned above the molds 1 and 2 by this forward and backward movement.

  The lower mold 1 is connected to an air supply pipe 20 for air assisting the extraction for each liner model. An air supply pipe 20 is also installed in the bolster 4, and the lower mold 1 is simply mounted on the bolster 4 and is connected by a joint installed on the lower mold bottom surface and the bolster upper surface. A similar joint is disposed between the bolster 4 and the lift table 5, and the air supply pipe 20 is connected by holding the bolster 4 on the lift table 5. Each air supply pipe 20 extends to the outside of the modeling apparatus, and includes a regulator 23 for adjusting the air pressure provided for each liner model and an electromagnetic valve 24 as an operation means for operating air supply / stop provided for each liner model. Connected to the air source. The electromagnetic valve 24 is operated at the time of mold removal by a control device that detects the height of the lift table 5.

  In FIG. 1, for convenience, the air supply pipe 20 outside the molding apparatus is drawn by a single line, and the regulator 23 and the solenoid valve 24 are drawn one by one. However, as shown in FIG. 2, 20 liner models 3 are provided. In this case, 20 air supply pipes 20 are provided, and one regulator 23 and one electromagnetic valve 24 are provided for each air supply pipe 20. An air supply pipe extending from an air source is branched and connected to the plurality of electromagnetic valves 24. 7 to 9 described later, the air supply system is simply illustrated as in FIG.

  As shown in FIG. 2, in the lower mold 1, a plurality of bottomed cylindrical liner models 3 are erected on the model support base 25 at intervals in the front-rear and left-right directions. Further, cylindrical guide rods 26 with bottoms for guiding the cutting die are erected at the four corners of the model support base 25. The draft angle of the liner model 3 is about 0.1 degree, and the draft angle of the guide rod 26 is 0 degree.

  As shown in FIG. 3, a large number of ridges 30 extending in the liner longitudinal direction are formed on the outer peripheral surface of the liner model 3 at intervals in the circumferential direction. The ridges 30 are for increasing the coupling strength between the cylinder liner and the cylinder block body. In other drawings except FIG. 3, the illustration of the ridges 30 of the liner model 3 is omitted or simplified.

  As shown in FIG. 4 (plan view), an air outlet 27 is opened at the center of the bottom of each liner model 3. That is, as shown in FIG. 5, an air hole 29 having an air outlet 27 is formed in the bottom wall of the liner model 3. The model support base 25 is formed with an air hole 31 continuous with the air hole 29 of the liner model 3, and the air supply pipe 20 to which air is supplied from the air supply pipe 20 is connected to the air hole 31. ing. As shown in FIG. 5, it is preferable to form a slit-shaped air outlet 27 by fitting a member 27 </ b> A having a plurality of slits into the air hole 29, in which case sand is filled into the air hole 29. There is an advantage that the amount can be reduced.

  As shown in FIG. 4, a vent hole 36 is provided around each liner model 3 and each guide rod 26 in the model support base 25 to draw air from the green sand to the lower side of the mold when squeezing. As shown in FIG. 5, the vent hole 36 is preferably formed in a slit shape by a slit member 36 </ b> A having a plurality of slits, like the air outlet 27. Although illustration is omitted, the upper mold 2 is also provided with a vent hole for drawing air from the green sand to the outside of the mold when squeezing.

  As shown in FIG. 6, a release agent supply pipe 37 that extends horizontally is provided in the release agent application station so as to move laterally above the lower mold 1. The release agent supply pipe 37 includes a plurality of release agent spray nozzles 38, and the release agent is the liner model 3 of the lower mold 1 and the guide rod 26 (note that the guide rod 26 is not shown in FIG. 6). The direction of the injection hole is appropriately changed so as to adhere to each inner peripheral surface, outer peripheral surface and bottom surface, and the upper surface of the model support base 25. In this case, the nozzle 38 for attaching the release agent mainly to the inner peripheral surface of each of the liner model 3 and the guide rod 26 is oriented in the vertical direction, and the release agent is mainly applied to the outer peripheral surface of each of the liner model 3 and the guide rod 26. The nozzle 38 for adhering the nozzle is directed obliquely downward. As the release agent, a water-based O / W emulsion is preferable.

(Mold molding method)
The molds 1 and 2 are transported onto the bolster 4 of the molding station by the transport means and held by the bolster 4, and then the mold release agent is sprayed by the plurality of release agent spray nozzles 38 once every two cycles. Applied.

  As shown in FIG. 7, the casting frames 7 and 8 are positioned above the molds 1 and 2 held by the bolster 4, and the louver hoppers 21 and 22 are positioned above the casting frames 7 and 8. By raising the lift table 5 by the frame setting cylinder 6, the molds 1 and 2 held by the bolster 4 are raised. As the molds 1 and 2 are raised, the cast frames 7 and 8 are placed on the molds 1 and 2 and are lifted from the roller 9 of the cast frame conveying device 11, and the fill frames 12 and 13 are 8 is lifted from the frame receiver 15 together with the frame 14. As the molds 1 and 2 are raised, the molds 1 and 2 are pressed against the louver hoppers 21 and 22 with the cast frames 7 and 8 and the fill frames 12 and 13 interposed therebetween (cast frame set state). In this state, green sand 39 is put on the molds 1 and 2 from the louver hoppers 21 and 22. After lifting the casting frames 7 and 8 from the rollers 9 of the casting frame conveying device 11 by raising the lift table 5, the leveling cylinder 16 is kept in the raised state.

  As shown in FIG. 8, a shuttle device (not shown) is driven, and the squeeze boards 17 and 18 of the squeeze head 19 are positioned above the molds 1 and 2 instead of the louver hoppers 21 and 22. The green sand 39 on the molds 1 and 2 is pressed and hardened by lowering the squeeze boards 17 and 18. At this time, air flows from the green sand 39 to the vent holes of the molds 1 and 2, so that the green sand can be compacted smoothly.

  As shown in FIG. 9, after the squeeze of the green sand 39 (molding of the molds 41 and 42) is completed, the lift table 5 is lowered by the frame setting cylinder 6. As the lift table 5 starts to descend, the electromagnetic valve 24 is operated to start supplying air to the bottoms of the liner model 3 and the guide rod 26. As the lift table 5 is lowered, the frames 14 of the fill frames 12 and 13 are placed on the frame receiver 15, and the cast frames 7 and 8 are received by the leveling cylinder 16 so as to be in a horizontal state. When the casting frames 7 and 8 are received by the leveling cylinder 16, the molds 41 and 42 are removed, and when the lift table 5 is slightly lowered from that time, air to the bottoms of the liner model 3 and the guide rod 26 is obtained. Stop supplying.

  After the lowering of the lift table 5 is finished, the leveling cylinder 16 is switched to the lowered state, so that the molds 41 and 42 are placed on the roller 9 of the casting frame conveying device 11 together with the casting frames 7 and 8 and conveyed to the next station.

  As shown in FIG. 10, when the mold 37 is removed from the mold 1, the liner model 3 forms a cylinder liner forming cavity 43, and the guide rod 26 forms a guide hole 44. For the sake of convenience, in FIG. 10, the draft of the liner model 3 is drawn larger than the actual draft.

  When the mold 41 is removed, the mold 41 receives a force in the removal direction by the air pressure applied to the mold 41 from the air outlet 27 at the bottom of the liner model 3. In this case, air pressure is applied to the entire lower surface of the mold columnar portion 41a in the liner model 3, and air rises while passing through the sand grains of the mold columnar portion 41a. The propulsive force by flowing air is also received, that is, the entire mold columnar portion 41a receives air pressure in the mold drawing direction. Further, the air flows between the inner surface of the liner model 3 and the mold columnar portion 41a, thereby reducing the punching resistance. For this reason, the mold 41 made of green sand is low in strength and hardness, but can be prevented from being destroyed during the mold drawing.

  Further, since the guide rods 26 having a draft angle of 0 degree are provided at the four corners of the mold 1, the guide rods 26 and the guide holes 44 serve as the guides for the removal of the mold. In other words, even if the die is advanced and a gap is formed between the mold 41 and the liner model 3 in the cavity 43 of the mold 41, no substantial gap is generated between the mold 41 and the guide rod 26. Therefore, the guide rod 26 prevents the mold 41 from sideways with respect to the mold 1 when the mold is removed, and the destruction of the mold 41 is avoided.

  The air supply pipe 20 is provided with a switching valve that can be switched between an air supply position and an atmosphere opening position, and the switching valve is set to the atmosphere opening position so that the air outlet 27 is used as a vent hole during squeezing. Also good.

1 Mold 3 Liner model (cylindrical model)
7 Casting frame 12 Filling frame 19 Squeeze head 21 Louver hopper (raw sand input means)
26 Guide rod (guide member)
27 Air outlet 36 Vent hole 39 Green sand 41 Mold 43 Cavity 44 Guide hole

Claims (2)

A mold making apparatus for molding a cylindrical casting,
A mold in which a plurality of cylindrical models are erected on a model support base at intervals; a casting frame set in the mold; a green sand feeding means for feeding green sand into the casting frame; and And a squeeze device that molds the green sand in the casting mold and molds the mold,
On the outer peripheral surface of the cylindrical model, a number of ridges extending in the drawing direction are formed at intervals in the circumferential direction,
At the bottom of the cylindrical model, an air outlet for applying air pressure from the bottom to the mold at the time of mold opening opens ,
The model support base is provided with a plurality of columnar guide members that form guide holes extending in the mold drawing direction in the mold, and the escape slope of the guide member is made smaller than the escape slope of the cylindrical model, or A casting mold making apparatus characterized in that the guide member has a draft angle of zero . In claim 1 ,
A casting mold making apparatus characterized in that a vent hole is formed around the cylindrical model of the model support base to vent air when the green sand is hardened and a mold is formed.

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