JP4284148B2 - Sand core molding machine - Google Patents

Description

  The present invention relates to a sand core molding apparatus.

  Some recent internal combustion engine cylinders are provided with a partition plate, also referred to as a tumble plate, in the intake port of the cylinder head. By controlling the airflow control valve arranged at the intake side end of the intake port, the intake air introduced from the intake port to the cylinder bore is drifted by the partition plate, and the tumble flow (longitudinal vortex flow) generated in the cylinder bore is strengthened, The fuel consumption is improved (see Patent Document 1).

  In the present specification, in the partition plate, the side on which the intake air of air or fuel gas flows is referred to as “intake side”, and the opposite side, that is, the cylinder bore side is referred to as “cylinder side”.

  In the case of casting the cylinder head, it is common to place a metal partition plate in the intake port molding sand core and cast and mold the partition plate. During casting of the cylinder head, each of the core and the partition plate rises in temperature due to heat from the molten metal and expands thermally. Here, the difference between the thermal expansion coefficient of the partition plate and the thermal expansion coefficient of the core that holds the partition plate is large, and the partition plate has a larger amount of thermal expansion than the core. For this reason, the partition plate may pressurize or spread the core, causing cracks or breakage in the core, and the molten metal may ooze out from the crack, creating a burr. In addition, due to the thermal expansion of the partition plate, the position of the partition plate may be shifted during casting of the cylinder head. Further, in the cylinder head as a product after the completion of casting, the partition plate may be loose in the product. There is also.

  For this reason, depending on the location where the burrs are generated, not only the deburring work in post-processing is extremely troublesome, but also the quality of the product is deteriorated due to the displacement of the partition plate and the play in the product. Therefore, the thermal influence must be fully considered for the partition plate.

The partition plate disclosed in Patent Document 1 is formed in a corrugated shape as a countermeasure against deformation caused by thermal expansion when casting the partition plate during casting of the cylinder head. However, the wave-shaped partition plate can absorb the thermal expansion in the radial direction of the intake port, but cannot absorb the thermal expansion in the axial direction. For this reason, it is not possible to limit the locations where burrs are generated due to the cracking of the core due to the difference in thermal expansion between the partition plate and the core, and the position of the partition plate and the play in the product are not sufficient. It cannot be suppressed to.
JP 2001-193469 A

  The present invention has been made in view of the above circumstances, and an object of the present invention is to facilitate the deburring work in post-processing by limiting the locations where burrs are generated due to cracking of the core.

The present invention that achieves the above object is characterized in that a partition plate for partitioning an intake port of a cylinder head into a plurality of ports forms sand cores for forming an intake port formed so as to be encased during casting of the cylinder head. In child molding equipment,
A loose piece provided movably toward the intake side end of the partition plate placed in the mold and provided with a sand removal portion for stealing core sand on the side of the intake side end; It is a sand core molding apparatus characterized by having.

  According to the present invention, because the sand removal portion of the loose piece forms the space portion in which the core sand on the suction side end portion of the partition plate is stolen in the suction port molding sand core, It is possible to limit or control the direction in which the partition plate thermally expands due to the heat of the heater to one direction toward the space, and to limit the occurrence of burrs caused by the cracking of the core to be limited in the post-processing burrs. It is possible to facilitate the taking operation.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, the cylinder head 10 having the partition plate 100 for the intake port 14 which is a premise of the present invention will be described. In the following description, the partition plate 100 for the intake port 14 is also referred to as a “tumble plate 100”.

  1 is a schematic cross-sectional view showing a cylinder head 10 of the engine, FIG. 2 is a cross-sectional view perpendicular to the axis of the intake port 14, FIG. 3 is a schematic view showing an air flow state in the cylinder head 10, and FIG. FIG.

  Referring to FIGS. 1 and 3, a cylinder head 10 is provided on an upper portion of a cylinder block 11, and includes an intake port 14 for introducing an intake air flow including air and fuel gas from an intake manifold 12 into the cylinder bore 13, and a cylinder bore. 13 has an exhaust port 15 for discharging exhaust gas after burning in the interior. The illustrated engine has one cylinder and four valves, and two intake valves 16 and two exhaust valves 17 are provided.

  A partition plate 100 is provided in the intake port 14 along the flow direction of intake air (open arrow) flowing from the intake side (outer end side in FIG. 3) toward the cylinder side. As shown in FIGS. 3 and 4, an intake manifold 12 provided with a control valve 18 is connected to the intake side of the partition plate 100. The intake port 14 is partitioned into an upper port 14u and a lower port 14d by the partition plate 100. When the lower port 14d is closed by the control valve 18, the intake air is accelerated and flows in the upper port 14u, and the cylinder bore A strong tumble flow (longitudinal vortex flow) will be formed within 13.

  In the intake port 14, the passage on the cylinder side is greatly bent, and if the position of the cylinder side end portion Ta of the tumble plate 100 varies, the characteristics of the air flow change, which greatly affects the generation state of the tumble flow. Therefore, the position of the cylinder side end portion Ta is an extremely important position. On the other hand, the position of the intake side end portion Tb of the tumble plate 100 is the side where the intake air is branched and the control valve 18 is provided. Therefore, even if the position varies, the characteristics of the airflow change. In general, it is not necessary to set the cylinder side end portion Ta as accurately as possible.

  Therefore, in the present embodiment, when casting the cylinder head 10, the position of the cylinder side end Ta of the tumble plate 100 is fixed and the position of the intake side end Tb is relatively free. Even if the tumble plate 100 is thermally affected during hot water, it can be absorbed on the intake side end portion Tb side.

  5A and 5B are a plan view and a side view showing the tumble plate 100 according to the present embodiment.

  As shown in FIGS. 5A and 5B, the tumble plate 100 according to the embodiment includes an intake port molding sand core 200 (see FIGS. 6 and 7) that forms the intake port 14 of the cylinder head 10. ) In advance and is cast when the cylinder head 10 is cast, and the intake port 14 of the cylinder head 10 is partitioned into a plurality of ports (upper port 14u and lower port 14d). In the following description, the intake port molding sand core 200 on which the tumble plate 100 is installed in advance is also referred to as “port core 200”.

  More specifically, the tumble plate 100 has a substantially rectangular shape, and is continuous with the side edge portions Tc and the side edge portions Tc that are to be cast in the molten metal when the cylinder head 10 is cast, and within the intake port 14. An intake side end Tb to be disposed on the upstream side of the intake flow, and a cylinder side end Ta to be disposed on the downstream side of the intake flow while continuing to the side edges Tc. ing. The inner part of each side edge part Tc is a partition part 103 that partitions the inside of the intake port 14. Reference numerals 101 and 102 in the figure indicate the side end face 101 and the end face 102 in the thickness direction at the side edge portions Tc, respectively.

  The material of the tumble plate 100 is preferably an aluminum alloy in consideration of recyclability.

  The thickness of the tumble plate 100 is preferably thin so as not to resist the intake air flowing through the intake port 14, but when the material of the tumble plate 100 is an aluminum alloy, the cast product of the cylinder head 10 is heat-treated. In consideration of the need to prevent thermal deformation at the time, the thickness is preferably about 1.5 mm or more.

  The tumble plate 100 may be chamfered on the intake side end Tb. There is a case where the end face of the cylinder head 10 to which the intake manifold 12 is connected is machined by a cutter or the like in post-processing after the casting of the cylinder head 10 is cast. In such a case, the cutting of the intake side end Tb of the tumble plate 100 is cut off. This is because the burrs can be suppressed more smoothly and the occurrence of burr during processing can be suppressed.

  Although the manufacturing method of the tumble plate 100 is not particularly limited, it is preferable to manufacture the tumble plate 100 by press molding from the viewpoint of easily and inexpensively manufacturing the tumble plate 100.

  6A is a perspective view showing the port core 200 in which the tumble plate 100 is previously installed and the sand stealing space 220 and the molten metal stopping sand wall 221 are formed, and FIG. 6B is the sand stealing space 220. The perspective view which shows the state which looked at the port core 200 from the side, FIG. 7 (A) (B) is the top view and side view which show the same port core 200. FIG. FIG. 8 is a schematic cross-sectional view showing a mold 300 in a sand core molding apparatus that molds the port core 200. In the following description, the mold 300 in the sand core molding apparatus for molding the port core 200 is abbreviated as “core mold 300”.

  When casting the cylinder head 10, first, the port core 200 shown in FIGS. 6 and 7 is formed using the core mold 300 shown in FIG. 8.

  The port core 200 is installed in a casting mold 400 for casting the cylinder head 10 (see FIG. 14) to form the intake port 14 of the cylinder head 10. This port core 200 is installed in advance so that the above-described tumble plate 100 protrudes to the outside so that both side edge portions Tc are cast in the molten metal.

  The port core 200 has a baseboard 201 on the outer side (also referred to as “outside the product shape”) than the region where the shape of the intake port 14 is formed (also referred to as “inside the product shape”). The product shape has a lot of contact with the molten metal and is susceptible to thermal deterioration. However, since the baseboard 201 has little contact with the molten metal, there is little influence of thermal deterioration of the binder of the core sand 210 during casting. Is a portion where the core strength is maintained as compared with the product shape. For this reason, due to the thermal expansion of the tumble plate 100 during the casting of the cylinder head 10, the port core 200 may be pressurized by the cylinder side end portion Ta, which may cause cracks or breakage in the product shape. If core breakage occurs in the product shape, deburring work in post-processing becomes extremely troublesome.

  Therefore, in the port core 200 of the present embodiment, the core sand 210 on the intake side end portion Tb side is stole, and the portion has a strength lower than the strength in the product shape where the strength decreases due to thermal deterioration, that is, The portion having the weakest strength in the port core 200 can be positively and stably set outside the product shape. This configuration is intended to stably release the internal stress due to the difference in thermal expansion between the tumble plate 100 and the core sand 210 outside the product shape.

  That is, the port core 200 includes a sand stealing space portion 220 formed by stealing the core sand 210 on the intake side end portion Tb, and a molten metal stopping sand wall that prevents the molten metal from entering the sand stealing space portion 220. 221. The sand stealing space 220 is a portion that becomes a space that allows thermal expansion of the tumble plate 100 due to the heat of the molten metal and absorbs the amount of elongation of the tumble plate 100. The molten metal stopping sand wall 221 is a thin and elongated portion formed only by the core sand 210 and is a portion that serves as a kind of dam for preventing the molten metal from entering the sand stealing space 220. Detailed functions of the sand stealing space 220 and the molten metal sand wall 221 will be described later.

  Both side edge portions Tc of the tumble plate 100 protruding to the outside are portions that make the holding more reliable when cast into the molten metal. The casting margin of the side edge portions Tc is not particularly limited, but is set to about 2 mm, for example.

  Referring to FIG. 8, the core mold 300 includes a plurality of partial molds including a core upper mold 301, a core lower mold 302, a loose piece 310, and the like. When these partial molds are brought into contact with each other, a cavity 303 for forming the port core 200 is formed therein. Core sand is blown into the cavity 303 and pressed to form the port core 200.

  FIG. 9 (A) is a schematic plan view for explaining the formation of the sand stealing space 220 by the loose piece 310 of the sand core molding apparatus, and FIG. 9 (B) is a line 9B-9B in FIG. 9 (A). 10A, 10B, and 10C are schematic side views for explaining the molding of the molten metal-prevented sand wall 221 by the loose piece 310 of the sand core molding apparatus, and 10B-10B in FIG. It is sectional drawing which follows a line, and is a detail drawing of 10C section of Drawing 10 (B). In addition, the code | symbol "320" in FIG. 9 has shown the sand blowing inlet which blows in core sand.

  In this embodiment, as shown in FIGS. 9 and 10, a plate-shaped movable loose piece 310 is used to form the sand theft space 220 and the molten metal-preserved sand wall 221. In general, the loose piece 310 is movably provided toward the intake side end portion Tb of the tumble plate 100 placed in the mold, and sand that steals the core sand 210 on the intake side end portion Tb side. A removal unit 311 is provided. Further, the loose piece 310 has a sand wall forming surface 312 for forming a molten metal stopping sand wall 221 that prevents the molten metal from entering the sand stealing space 220 to be formed in the port core 200 by the sand removing unit 311. Is provided.

  More specifically, the loose piece 310 is indicated by a two-dot chain line in FIGS. 9A and 9B, and the tip portion shown on the left side in the drawing has a sand removal size corresponding to the sand theft space portion 220. A part 311 is provided. The top surface of the sand removing portion 311 is formed to be inclined in a tapered shape. From the sand removing portion 311 to the rear end portion shown on the right side in the figure, an inclined upper surface is formed. The lower surface of the loose piece 310 is formed substantially horizontally and is slidable with respect to the upper surface of the core lower mold 302. When the port core 200 is formed, the loose piece 310 is set in a state in which the front end surface of the sand removing portion 311 is in contact with the intake side end portion Tb of the tumble plate 100.

  Referring to FIGS. 10A and 10B, a sand wall molding surface 312 that is tapered in a tapered shape is provided on the side surface of the sand removing portion 311 of the loose piece 310. As shown in FIG. 10C, the sand core molding surface 312 allows the core sand 210 to enter, and a molten metal-preventing sand wall 221 is formed on the side surface of the port core 200 after the molding (FIG. 6A). See also).

  FIG. 11 is a cross-sectional view showing a state in which the leading end surface of the suction side end Tb of the tumble plate 100 placed in the mold is pressed by the loose piece 310 fixing means. 12A and 12B are a schematic plan view and a schematic side sectional view conceptually showing sand flow when core sand is blown, and FIG. 12C shows a mold 300 by means of fixing means 330 of the loose piece 310. It is sectional drawing which shows the state which also pressed down the upper end surface 102 of the thickness direction of the inhalation | air-intake side edge part Tb in the tumble board 100 mounted in the inside.

  The loose piece 310 of the present embodiment is further provided with a fixing means 330 that regulates the position of the tumble plate 100 with respect to the mold 300. The fixing means 330 is configured by a first pressing member 331 (see FIG. 11) that presses the front end surface of the suction side end Tb of the tumble plate 100 mounted in the mold 300, or is mounted in the mold 300. In addition, the tumble plate 100 may be configured by a second pressing member 332 (see FIG. 12C) that also presses the upper end surface 102 in the thickness direction of the suction side end Tb.

  First, the first pressing member 331 will be described with reference to FIG.

  When the port core 200 is molded, the core sand 210 is blown in a state where the tumble plate 100 is previously placed in the core mold 300. At this time, in a form in which the tumble plate 100 is set on the seat 333 formed on the peripheral edge of the cavity of the lower core mold 302 and the upper mold 301 is closed and the tumble plate 100 is held, the tumble plate 100 is the core mold. It is difficult to position so that it does not shift within 300, and there is a possibility that positional deviation of tumble plate 100 with respect to mold 300 will occur.

  Therefore, the tip end portion of the loose piece 310 that abuts the intake side end portion Tb is formed on the inclined surface 334, and the first pressing member 331 can be configured by the inclined surface 334. According to the first pressing member 331, the closing direction of the loose piece 310, which is a member that presses the tumble plate 100, is set in a direction close to the extension line 335 in the direction in which the tumble plate 100 can move along the seat 333. The As a result, the force that presses the loose piece 310 acts as a force that presses the tumble plate 100 via the inclined surface 334, prevents the tumble plate 100 from being displaced relative to the mold 300, and the tumble in the direction in which it can move along the seat 333. The positioning accuracy of the plate 100 can be increased.

  Although the loose piece 310 is shown to move in the horizontal direction, the loose piece 310 is driven along the extension line 335 from the viewpoint of increasing the positioning accuracy of the tumble plate 100 in the direction in which the loose piece 310 can move along the seat 333. It is good also as a structure.

  Next, the second pressing member 332 will be described with reference to FIG.

  When the port core 200 is molded, the core sand 210 is blown in a state where the tumble plate 100 is previously placed in the core mold 300. At this time, a flow difference may occur between the upper side and the lower side of the tumble plate 100 in the core sand 210 that flows as indicated by arrows in FIGS. As a result of the sand flow difference acting as a force 336 for moving the tumble plate 100 in the vertical direction (thickness direction), the tumble plate 100 may be misaligned with respect to the mold 300.

  Therefore, the tip of the loose piece 310 that contacts the intake side end Tb is formed on the inclined surface 334, and further, an engagement protrusion 337 that engages with the upper end surface 102 in the thickness direction of the intake side end Tb is provided. The second pressing member 332 can be configured by the inclined surface 334 and the engaging protrusion 337. According to the second pressing member 332, the vertical movement of the tumble plate 100 due to the sand flow difference can be further suppressed, the positional deviation of the tumble plate 100 with respect to the mold can be prevented, and the tumble plate 100 can move along the seat 333. It is possible to improve the positioning accuracy of the tumble plate 100 not only in the direction but also in the vertical direction (thickness direction).

  FIGS. 13A to 13E are views showing a molding process of the port core 200 in the mold 300 in the sand core molding apparatus.

  When molding the port core 200, first, the tumble plate 100 is set on the seat 333 of the core lower mold 302 with the loose piece 310 retracted (FIGS. 13A and 13B). .

  Next, the loose piece 310 is closed (forward drive), and the sand removal unit 311 is set in a state where the tip end surface of the sand removal unit 311 is in contact with the intake side end Tb of the tumble plate 100 (FIG. 13C). Further, the position of the tumble plate 100 with respect to the mold 300 is regulated by the fixing means 330 constituted by the first pressing member 331 or the second pressing member 332.

  The core sand 210 is blown into the cavity 303 formed by closing the upper core 301 for the core from the sand blowing port 320 (FIGS. 13D and 13E).

  After the core sand 210 that has been blown is pressed and solidified, the core upper mold 301 is opened to divide the core mold 300. At this time, the loose piece 310 moves backward in a direction orthogonal to the dividing direction of the core mold 300 and is released (see FIG. 9B). As a result, the port core 200 is taken out from the core mold 300.

  In the port core 200 thus formed, a sand stealing space portion 220 is formed by the sand removing portion 311 of the loose piece 310, and a molten metal-preventing sand wall 221 is formed by the sand wall forming surface 312 of the loose piece 310. The sand stealing space 220 is formed to extend horizontally from the intake side end Tb of the tumble plate 100 by the movement of the loose piece 310. Here, the BB line in FIG. 9B shows a surface to be machined later, but the port core 200 of this embodiment is relatively easy to break on the side to be removed by this machining. is doing. This is because if the port core 200 is damaged, it is preferable to use the machined side to facilitate the subsequent correction and reduce the possibility of defective products.

  FIG. 14 is a cross-sectional view showing a state in which the port core 200 is installed in a casting mold 400 for casting the cylinder head 10.

  As shown in FIG. 14, the molded port core 200 is incorporated into a casting mold 400 for molding the cylinder head 10. The casting mold 400 includes an upper mold 401, a lower mold 402, and a side mold 403. When the port core 200 is supported between the lower mold 402 and the side mold 403 and covered with the upper mold 401, the cylinder head 10 is placed inside. A cavity 404 is formed for molding. In addition, the code | symbol "405" in a figure is a core for water jacket shaping | molding. As the casting method, for example, a low pressure casting method (LPDC) is adopted.

  In this state, when a molten metal made of aluminum alloy or other metal is poured into the cavity 404 from the gate (not shown), the cylinder head 10 as shown in FIG. 1 is formed. The tumble plate 100 provided in the port core 200 is thermally expanded by the heat of the molten metal.

  In the present embodiment, the port core 200 on which the tumble plate 100 is placed is formed with the sand stealing space portion 220 on the side of the intake side end Tb of the tumble plate 100 by the sand removing portion 311 of the loose piece 310. It is. The sand stealing space 220 forms an expansion allowance space that allows thermal expansion of the tumble plate 100, and even if the tumble plate 100 is thermally expanded due to heat from the molten metal, the applied pressure acts on the port core 200 and breaks. It is a part that prevents cracks from occurring.

  When the port core 200 having such a sand stealing space 220 is assembled into the casting mold 400 and poured into the cavity 404, the tumble plate 100 is casted on both side edges Tc, and the molten metal solidifies. The whole of both side edge portions Tc is fixed.

  Here, the tumble plate 100 is thermally expanded by the heat of the molten metal, and this thermal expansion is concentrated in the intake side end Tb that is easily expanded and occurs in the sand stealing space 220, and the intake side end of the tumble plate 100 is The portion Tb only slides within the sand stealing space 220. For this reason, it is possible to limit or control the direction in which the tumble plate 100 thermally expands due to the heat of the molten metal to one direction from the cylinder side end portion Ta toward the intake side end portion Tb. Therefore, the port core 200 is not pressurized by the cylinder side end portion Ta, and is cracked or broken in an area (inside the product shape) important for forming the shape of the intake port 14 in the port core 200. Etc. will not occur.

  Even if the thermal expansion of the tumble plate 100 is large, the port core 200 reduces the strength on the intake side end portion Tb side by the sand theft space portion 220 compared to the cylinder side end portion Ta side. Cracks occurring in the core 200 can be induced or induced on the intake side end Tb side or the baseboard 201 side. The burr resulting from the cracking of the port core 200 occurs not in the cylinder head 10 as a product after completion of casting but outside the product shape on the intake manifold 12 side that does not affect the product performance. Therefore, it is not necessary to perform the subsequent deburring work easily or to be performed. In addition, since the sand stealing space 220 is formed by the loose piece 310, the shape of the sand stealing space 220 becomes constant, and cracks that may occur in the port core 200 are stably induced on the intake side end Tb side. Can be made.

  In addition, the port core 200 is formed with a melt-preventing sand wall 221, and both ends of the sand stealing space 220 are covered with the melt-preventing sand wall 221, and the molten metal can directly enter the sand stealing space 220. Is prevented. Therefore, when the molten metal is poured, the molten metal does not enter the sand stealing space 220 and hinder the expansion of the tumble plate 100 toward the suction side end Tb, and the thin and slender molten metal stopper sand wall 221 The tumble plate 100 is destroyed by the expanding tumble plate 100, and the tumble plate 100 slides in the sand stealing space 220. In other words, the molten metal stopping sand wall 221 does not hinder the thermal expansion of the tumble plate 100, and a crack that can occur in the port core 200 can be stably induced on the intake side end portion Tb side.

  Further, since the loose piece 310 is provided with fixing means 330 that regulates the position of the tumble plate 100 with respect to the mold 300, the fixing means 330 prevents the positional deviation of the tumble plate 100 with respect to the port core 200. For this reason, when the port core 200 is incorporated in the casting mold 400, the tumble plate 100 can be disposed in a normal design position within the casting mold 400. Through this, when the both side edge portions Tc of the tumble plate 100 are cast into the molten metal, the position of the tumble plate 100 with respect to the intake port 14 is regulated, and the tumble plate 100 is placed in the design proper position in the cylinder head 10. It becomes possible to arrange in.

  As described above, according to the present embodiment, even if the tumble plate 100 is thermally expanded, the tumble plate 100 is accurately cast in a state where the position of the cylinder side end portion Ta, which is an important position, is maintained. Accordingly, the positional deviation of the tumble plate 100 and the play in the product are sufficiently suppressed to improve the product quality, and further, the occurrence of burrs caused by cracks in the port core 200 is limited. It is possible to facilitate deburring work during processing.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an application for facilitating a deburring operation in post-processing by limiting the occurrence of burrs caused by cracking of the core.

It is a schematic sectional drawing which shows the cylinder head of an engine. It is a cross-sectional view perpendicular to the axis of the intake port. It is the schematic which shows the airflow state in a cylinder head. FIG. 4 is a schematic plan view of FIG. 3. 5A and 5B are a plan view and a side view showing the tumble plate according to the present embodiment. FIG. 6A is a perspective view showing a port core in which a tumble plate is preliminarily installed and a sand stealing space portion and a molten metal stopping sand wall are formed, and FIG. 6B is a port core from the sand stealing space portion side. It is a perspective view which shows the state which looked at. 7A and 7B are a plan view and a side view showing the port core. It is a schematic sectional drawing which shows the type | mold in the sand core molding apparatus which molds a port core. FIG. 9A is a schematic plan view for explaining the formation of the sand stealing space by the loose piece of the sand core molding apparatus, and FIG. 9B is a cross section taken along the line 9B-9B in FIG. 9A. FIG. 10 (A), (B), and (C) are schematic side views for explaining the molding of a molten metal stopping sand wall by the loose piece of the sand core molding apparatus, cross-sectional views taken along the line 10B-10B in FIG. It is detail drawing of the 10C section of FIG.10 (B). It is sectional drawing which shows the state which hold | suppressed the front end surface of the suction side edge part in the tumble board mounted in the type | mold by the loose piece fixing means. 12 (A) and 12 (B) are a schematic plan view and a schematic side sectional view conceptually showing sand flow when core sand is blown, and FIG. 12 (C) is placed in a mold by a loose piece fixing means. It is sectional drawing which shows the state which pressed down also the upper end surface of the thickness direction of the inhalation | air-intake side edge part in the placed tumble board. FIGS. 13A to 13E are views showing a molding process of the port core in the mold in the sand core molding apparatus. It is sectional drawing which shows the state which installed the port core in the casting die which cast-molds a cylinder head.

Explanation of symbols

10 cylinder head,
14 intake port,
100 tumble plate (partition plate for intake port),
102 end face in the thickness direction,
200 port core (sand core for molding intake port),
210 core sand,
220 Sand stealing space,
221 Sand wall with molten metal
300 Core type (type of sand core molding device),
310 loose pieces,
311 Sand removal section,
312 Sand wall molding surface,
330 fixing means,
400 casting mold,
Ta cylinder side end,
Tb Inlet side end,
Tc Side edge.

Claims (3)

In a sand core molding apparatus for molding an intake port molding sand core installed so that a partition plate that divides the intake port of the cylinder head into a plurality of ports is cast when the cylinder head is cast.
A loose piece provided movably toward the intake side end of the partition plate placed in the mold and provided with a sand removal portion for stealing core sand on the side of the intake side end; A sand core molding apparatus characterized by comprising:   The loose piece is provided with a sand wall molding surface for molding a molten metal stopping sand wall that prevents the molten metal from entering the sand stealing space portion to be molded into the suction port molding sand core by the sand removing portion. The sand core molding apparatus according to claim 1, wherein: The sand core molding apparatus according to claim 1, wherein the loose piece is provided with fixing means for restricting a position of the partition plate with respect to the mold.

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