JP2015080801A - Die device for casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a port for air exhaust and feeding at a desired position in a cylinder head.SOLUTION: The die device for casting has a lower die 12. Among valve seat part formation parts 26a-26p formed on the lower die 12, the valve seat part formation parts 26a, 26c, 26n, 26p disposed on outermost parts in a parallel direction have a first stopper part 30 having an inclined first stopper surface 28. Among port formation parts 40a-40p of port formation sand cores 22a, 22b, the port formation parts 40a, 40c, 40n, 40p disposed on the outermost parts in the parallel direction have a second stopper part 44 having a second stopper surface 42 facing the first stopper surface 28.

Description

  The present invention relates to a casting mold apparatus for obtaining a cylinder head having a plurality of combustion chambers arranged in parallel along the longitudinal direction.

  A cylinder head constituting the internal combustion engine is formed with a plurality of combustion chambers into which lean fuel and air are introduced, and a port communicating with each combustion chamber. The boundary between the combustion chamber and the port is a valve seat portion in which a valve seat on which the cam valve is seated and separated is disposed.

  This type of cylinder head is generally obtained by low pressure casting. In this case, the casting mold apparatus includes a lower mold 1 shown in FIG. 8, an upper mold (not shown) that approaches or separates from the lower mold 1, and a space between the lower mold 1 and the upper mold. A plurality of sliding molds (not shown) interposed between the lower mold 1, the upper mold, and the sliding mold form a cavity.

  Here, the combustion chamber is formed by a combustion chamber forming portion 2 provided in the lower mold 1. The combustion chamber forming portion 2 is provided with a valve seat portion forming portion 3 for forming the valve seat portion.

  The port is formed by a sand core 5 having a port shaping portion 4. One end of the sand core 5 is provided with a skirting board portion 6, and the skirting board portion 6 is supported by a skirting board base 7 formed so as to protrude vertically upward from the lower mold 1 and a sliding mold. On the other hand, the tip of the port shaping part 4 faces the valve seat part molding part 3.

  In this state, a molten aluminum alloy is poured into the cavity, and the molten metal cools and solidifies to obtain a cylinder head. Of course, in the cylinder head, a combustion chamber is formed by the combustion chamber forming portion 2 of the lower mold 1, and a port is formed by the port shaping portion 4 of the sand core 5.

  By the way, in the process where the molten metal solidifies after casting to become a cast product (cylinder head), the cast product tends to solidify and shrink from the outer edge toward the inside. Along with this, as indicated by the broken line in FIG. 8, the port shaping portion 4 of the sand core 5 is displaced from the position of the alternate long and short dash line to the inside of the lower mold 1, and the outer edge of the cylinder head is directed to the inside. It becomes a shape like this (curvature deformation). If the degree of curvature increases, there is a concern that the shape of the port is affected and engine characteristics as designed cannot be obtained.

  In order to avoid such problems, Patent Documents 1 to 5 propose a configuration for positioning and fixing the sand core during casting. That is, a concave space (or convex portion) is formed in the sand core, and a convex portion (or concave space) to be inserted into the concave space (or convex portion) is formed in the valve seat molding portion. .

JP-A-6-344077 Japanese Patent Laid-Open No. 10-71451 JP 2003-39137 A JP 2008-771 A JP 2002-239714 A

  In the techniques described in Patent Documents 1 to 5, the sand core and the valve seat portion molding portion must be connected by manually inserting a convex portion into the concave space. For this reason, it is difficult to set the sand core efficiently on the lower mold. Moreover, in this case, it is necessary to remove the sand remaining in the concave space after the sand core is collapsed.

  For the above reasons, it is not easy to efficiently obtain a cylinder head that is a cast product in the conventional technique in which the sand core for forming the port of the cylinder head does not cause a positional shift.

  The present invention has been made in order to solve the above-described problems, and provides a casting mold apparatus capable of efficiently obtaining a cylinder head while avoiding misalignment of a sand core. Objective.

To achieve the above object, the present invention provides a casting mold apparatus for obtaining a cylinder head having a combustion chamber.
A port-forming sand core comprising a plurality of port shaping portions for forming each of a plurality of ports communicating with the combustion chamber;
A mold comprising a baseboard for supporting the baseboard part of the port forming sand core;
Have
The mold is further formed to protrude from a bottom wall of a combustion chamber molding portion that molds the combustion chamber, and extends from the outer side to the inner side of the mold, and the extending direction of the baseboard portion A plurality of valve seat part forming parts facing each of the plurality of port shaping parts arranged substantially parallel to the
A portion of the upper end surface of the plurality of valve seat portion molding portions located on the outermost side in the parallel direction protrudes inward of the mold, as compared with other portions, so that the mold A first stopper portion having a surface facing the outer side of the mold is erected,
And the part which faces the outer side of the mold of the tip part of the plurality of port shaping parts located in the outermost direction in the parallel direction protrudes as compared with other parts, so that the first A second stopper portion is provided so as to be opposed to the first stopper portion and blocked by the first stopper portion.

  In the casting mold apparatus adopting such a configuration, when the port shaping portion is about to be displaced inward of the die, the second stopper portion provided in the port shaping portion is a valve seat. The first stopper part provided in the part molding part is dammed up. As a result, the port shaping portion is positioned and fixed, and eventually it is prevented from causing a positional shift.

  Therefore, the port can be obtained in a desired shape at a preset position. In an internal combustion engine (engine) having a cylinder head in which such a port is formed, it becomes easy to obtain desired engine characteristics.

  Moreover, in this case, the first stopper portion faces the second stopper portion as the skirting board portion is supported by the skirting board stand. That is, it is not particularly necessary to perform an operation for making the second stopper portion face the first stopper portion. Of course, it is not necessary to connect the first stopper portion and the second stopper portion to each other. Accordingly, the port forming sand core can be efficiently set in the mold.

  In addition, neither a concave space is formed in the valve seat portion molding portion nor a convex portion that is inserted into the concave space is formed in the sand core for port formation. Therefore, it is not necessary to remove the sand remaining in the recessed space of the valve seat portion molding portion.

  For the reasons described above, the cylinder head can be obtained efficiently.

  In addition, it is preferable that the surface which faces the outer side of the mold of the first stopper portion is an inclined surface which is inclined so as to rise from the outer side to the inner side of the mold. In this case, the surface functions as a draft and it is easy to remove the cylinder head.

  When the positional deviation of the port shaping parts other than the port shaping part located at the outermost position in the parallel direction is very small, the first stopper part is placed in the parallel direction outermost part of the plurality of valve seat part molding parts. You may make it provide only in what is located outside. In this case, it is needless to say that the second stopper portion may be provided only on the outermost one in the parallel direction among the plurality of port modeling portions.

  By the way, among the plurality of port shaping parts, those located in the middle part in the parallel direction tend to shrink in a direction away from the baseboard during solidification. Regardless of this contraction, a third stopper portion is provided in the valve seat portion molding portion located in the parallel direction abdomen so that the port located in the parallel direction abdomen has a desired shape and position, and It is preferable to provide a fourth stopper portion.

  Specifically, the part on the side away from the baseboard is projected on the upper end surface of the plurality of valve seat part molding parts located in the middle part in the parallel direction as compared with the other parts. Thus, the third stopper portion having a surface facing the baseboard is erected. On the other hand, the third portion is formed by projecting a portion facing the skirting board to a tip portion of the plurality of port shaping portions located in the middle portion in the parallel direction, compared to the other portions. A fourth stopper portion that is blocked by the third stopper portion is provided opposite to the stopper portion.

  When such a third stopper portion is provided, the inclined surface is inclined so that the surface of the third stopper portion facing the baseboard is raised from the side close to the baseboard toward the side away from the baseboard. It is preferable that In this case, since the surface also functions as a draft, it is easier to separate the cylinder head.

  According to the present invention, among the plurality of valve seat portion molding portions, the portion facing the inner side of the mold protrudes from the upper end surface of the one located at the outermost side in the parallel direction as compared with the other portions. A first stopper portion is erected, and a second portion facing the first stopper portion is disposed at a distal end portion of a plurality of port forming portions that constitute the port forming sand core and is located at the outermost side in the parallel direction. A stopper is provided.

  In the casting mold apparatus adopting such a configuration, when the port shaping portion is about to be displaced inward of the die, the second stopper portion provided in the port shaping portion is a valve seat. The first stopper part provided in the part molding part is dammed up. As a result, the port shaping portion is prevented from being displaced, so that a cylinder head in which a port having a desired shape is formed at a preset position can be obtained. Therefore, it becomes easy to obtain desired engine characteristics.

  In addition, in this case, the port forming sand core can be efficiently set in the mold, and the work for removing the sand remaining in the concave space of the valve seat portion molding portion is not required. For this reason, a cylinder head can be obtained efficiently.

It is a principal part schematic longitudinal cross-sectional view of the die apparatus for casting which concerns on embodiment of this invention. It is a top view which shows the state which supported the sand core for port formation in the lower mold | type which comprises the said casting mold apparatus. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. The principal part front view which expanded and showed the valve seat part shaping | molding part in which the 1st stopper part was provided in the parallel direction outermost part, and the port shaping part in which the 2nd stopper part was provided facing it It is. It is the principal part side view which expanded and showed the valve seat part shaping | molding part which was located in the parallel direction middle part, and was provided with the 3rd stopper part, and the port shaping | molding part provided with the 4th stopper part facing it. is there. Enlarging the valve seat part formed with the first stopper part biased to the outer side of the mold (lower mold) from the diameter position, and the port forming part provided with the second stopper part facing it It is the principal part front view shown. Enlarging the valve seat part forming part provided with the first stopper part biased to the inner side of the mold (lower mold) from the diameter position, and the port forming part provided with the second stopper part facing it It is the principal part front view shown. It is a top view which shows the state which supported the sand core for port formation in the lower mold | type which comprises the casting die apparatus which concerns on a prior art.

  Preferred embodiments of a casting mold apparatus according to the present invention will now be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic longitudinal sectional view of a main part of a casting mold apparatus 10 according to the present embodiment. The casting mold apparatus 10 includes a lower mold 12, a first side mold 14 and a second side mold 16 as sliding molds, and an upper mold 18, and the lower mold 12 and the first side mold 14. In the cavity 20 formed by the second side mold 16 and the upper mold 18, port forming sand cores (hereinafter also simply referred to as “sand cores”) 22 a and 22 b are arranged.

  The casting mold apparatus 10 is for obtaining a cylinder head (for example, see FIG. 1 of JP-A-2000-33459) by casting, and the shape of the cavity 20 corresponds to the shape of the cylinder head. Since this type of cylinder head is well known, its detailed description is omitted.

  In this case, the casting mold apparatus 10 is for casting a cylinder head for a four-cylinder engine. Therefore, as shown in FIG. 2, four combustion chamber forming portions 24 a to 24 d for forming the combustion chamber of the cylinder head are formed on the bottom wall of the lower mold 12. The combustion chamber forming portions 24a to 24d are arranged in parallel along the longitudinal direction of the lower mold 12 (the arrow X direction in FIG. 2).

  In the present embodiment, each of the combustion chamber forming portions 24a to 24d is provided with four valve seat portion forming portions for providing a valve seat portion in the cylinder head. That is, the lower mold 12 has a total of 16 valve seat part forming portions. Hereinafter, for convenience of explanation, reference numerals of the valve seat part forming part provided in the combustion chamber forming part 24a are 26a to 26d. Further, reference numerals 26e to 26h of the valve seat part molding part provided in the combustion chamber molding part 24b, reference numerals 26i to 26l of the valve seat part molding part provided in the combustion chamber molding part 24c, and the combustion chamber molding part. The reference numerals of the valve seat part forming portion provided at 24d are 26m to 26p.

  The valve seat portion molding portions 26a to 26p are arranged in parallel along the longitudinal direction of the lower die 12 (the direction of the arrow X in FIG. 2) from the outer side to the inner side of the lower die 12. And the valve seat part molding part 26b, 26d, 26e, 26g, 26j, 26l, 26m, and 26o in this form a cylindrical shape close to a truncated cone shape, and vertical from each upper end surface of the combustion chamber molding parts 24a to 24d. It protrudes upward (in the direction of arrow Z in FIG. 1).

  On the other hand, the four valve seat portion molding portions 26a, 26c, 26n, and 26p located at the end portions in the longitudinal direction (in other words, the outermost side) have upper end portions as shown in FIGS. It has a shape that is partially cut away. More specifically, as shown in FIG. 4 in which the main part of the valve seat part molding part 26n is enlarged, the part facing the inner side of the lower mold 12 is the other part on the upper end surface of the valve seat part molding part 26n. It protrudes compared to. Thereby, the 1st stopper part 30 which has the 1st stopper surface 28 which faces the outer side of the lower mold | type 12 is erected.

  Similarly, in the valve seat portion molding portions 26a, 26c, and 26p, the portions facing the inner side of the lower mold 12 protrude from the upper end surfaces as compared with the other portions (see FIGS. 2 and 3). . That is, the first stopper portion 30 having the first stopper surface 28 facing the outer side of the lower mold 12 is also erected on the valve seat portion molding portions 26a, 26c, and 26p.

  Each first stopper surface 28 is formed as an inclined surface that is inclined so as to rise from the outer side to the inner side of the lower mold 12. The inclination angle of the first stopper surface 28 with respect to the vertical line is preferably 1 ° to 5 °.

  In addition, as shown in FIGS. 1, 2 and 5, the four valve seat part molding parts 26f, 26h, 26i, and 26k located in the middle part in the parallel direction are also partially cut off at the upper ends. It has a shape like this. That is, on the upper end surfaces of these valve seat portion forming portions 26f, 26h, 26i, and 26k, the portions that are separated from the baseboards 32a and 32b, which will be described later, protrude from the other portions. Thereby, the 3rd stopper part 36 which has the 3rd stopper surface 34 which faces the baseboard 32a, 32b is standingly arranged.

  Each of the third stopper surfaces 34 is formed as an inclined surface that is inclined so as to rise from the side close to the baseboards 32a and 32b toward the side away from it. The inclination angle of the third stopper surface 34 with respect to the vertical line is preferably 1 ° to 5 °.

  As shown in FIG. 1, the baseboards 32a and 32b are formed on the upper end surface of the lower mold 12 so as to be directed vertically upward. These skirting boards 32 a and 32 b extend along the longitudinal direction of the lower mold 12.

  The sand cores 22a and 22b are supported on the baseboards 32a and 32b, respectively. These sand cores 22a and 22b are for forming ports for supply and exhaust in the cylinder head. In addition, although the component which attached | subjected the referential mark 37 is also a sand core, this sand core 37 shape | molds cavities etc. other than the said port.

  As can be understood from FIG. 2, the sand cores 22a and 22b have baseboard portions 38a and 38b respectively sandwiched between the baseboard bases 32a and 32b and the first side mold 14 and the second side mold 16. . Since the baseboard portions 38a and 38b extend along the longitudinal direction of the lower mold 12, the valve seat portion forming portions 26a, 26b, 26e, 26f, 26i, 26j, 26m, and 26n are along the baseboard portion 38a. The valve seat part molding parts 26c, 26d, 26g, 26h, 26k, 26l, 26o, and 26p are arranged substantially parallel in parallel along the baseboard part 38b.

  The sand cores 22a and 22b further have port shaping portions 40a to 40p that protrude substantially horizontally from the baseboard portions 38a and 38b toward the cavity 20 and are curved toward the valve seat portion forming portions 26a to 26p. Provided. As will be described later, when the mold clamping is performed, each end of the port shaping portions 40a to 40p faces each of the valve seat portion molding portions 26a to 26p.

  The tip of each of the port forming parts 40b, 40d, 40e, 40g, 40j, 40l, 40m, 40o facing the flat upper end surface of the valve seat part forming parts 26b, 26d, 26e, 26g, 26j, 26l, 26m, 26o The surface is formed flat. On the other hand, the front end portions of the port shaping portions 40a, 40c, 40n, and 40p that face the upper end surfaces of the valve seat portion forming portions 26a, 26c, 26n, and 26p provided with the first stopper portion 30 have the first A second stopper portion 44 having a second stopper surface 42 inclined at an angle corresponding to the angle of the first stopper surface 28 is formed to project.

  The second stopper surface 42 faces the first stopper surface 28 through a slight clearance of about 0.5 mm at the maximum. That is, the second stopper surface 42 is an inclined surface that faces the inner side of the lower mold 12 and is inclined so as to descend from the inner side toward the outer side. Even if the clearance is not formed (in other words, even if the first stopper surface 28 and the second stopper surface 42 are in contact with each other), there is no particular problem.

  Further, a third stopper is provided at the tip of each of the port shaping portions 40f, 40h, 40i, 40k facing the upper end surfaces of the valve seat portion forming portions 26f, 26h, 26i, 26k provided with the third stopper portion 36. A fourth stopper portion 48 having a fourth stopper surface 46 inclined at an angle corresponding to the angle of the surface 34 is formed to protrude.

  The fourth stopper surface 46 faces the third stopper surface 34 with a slight clearance of about 0.5 mm at the maximum. That is, the fourth stopper surface 46 is an inclined surface that faces the side away from the baseboards 32a and 32b and is inclined so as to descend from the side away from the baseboards 32a and 32b toward the adjacent side. is there. Similarly to the above, even if no clearance is formed between the third stopper surface 34 and the fourth stopper surface 46 (in other words, even if the third stopper surface 34 and the fourth stopper surface 46 are in contact with each other), in particular There is no problem.

  The first side mold 14 and the second side mold 16 shown in FIG. 1 slide on the upper end surface of the lower mold 12 under the action of a drive mechanism (for example, a hydraulic cylinder) (not shown). The sliding direction is the arrow Y direction shown in FIGS.

  The first side mold 14 and the second side mold 16 are formed with holding recesses 50 and 50 that can be fitted into the baseboard portions 38a and 38b of the sand cores 22a and 22b, respectively (see FIGS. 1 and 3). ). In other words, the baseboard portions 38a and 38b are fitted into the holding recesses 50 and 50 during mold clamping.

  The upper die 18 is lowered or raised so as to be relatively close to or separated from the lower die 12 under the action of a drive mechanism (for example, a hydraulic cylinder) (not shown). Of course, the mold is clamped as it descends, and as a result, the cavity 20 is formed. On the other hand, the mold is opened by raising.

  The casting mold apparatus 10 according to the present embodiment is basically configured as described above. Next, its operation and effect will be described in relation to a casting operation for obtaining a cylinder head.

  First, the baseboards 38a and 38b of the sand cores 22a and 22b are supported by the baseboards 32a and 32b of the lower mold 12, respectively. The baseboard portions 38a and 38b and the baseboard bases 32a and 32b are provided with engagement portions / engaged portions (not shown) that engage with each other (for example, concave portions and convex portions). It is avoided that 22a, 22b falls off from the baseboards 32a, 32b. At this time, the front end surfaces of the port shaping portions 40b, 40d, 40e, 40g, 40j, 40l, 40m, 40o are respectively formed on the valve seat portion forming portions 26b, 26d, 26e, 26g, 26j, 26l, 26m, 26o. Opposite the flat upper end surface.

  On the other hand, the second stopper of the second stopper portion 44 of the port shaping portions 40a, 40c, 40n, and 40p is formed on the first stopper surface 28 of the first stopper portion 30 of the valve seat portion forming portions 26a, 26c, 26n, and 26p. The surface 42 faces. Further, the fourth stopper surface 46 of the fourth stopper portion 48 of the port shaping portions 40f, 40h, 40i, and 40k is formed on the third stopper surface 34 of the third stopper portion 36 of the valve seat portion forming portions 26f, 26h, 26i, and 26k. Opposite.

  Thus, by supporting the baseboard portions 38a and 38b of the sand cores 22a and 22b with the baseboard bases 32a and 32b, respectively, the first stopper surface 28 and the second stopper surface 42 are opposed to each other, and the third stopper is provided. The surface 34 and the fourth stopper surface 46 can be opposed to each other. In the present embodiment, it is only necessary to obtain the facing state in this way, and the first stopper portion 30 and the second stopper portion 44 are connected, or the third stopper portion 36 and the fourth stopper portion 48 are connected. do not have to. Of course, unlike the prior art, no convex portion is inserted into the concave space.

  Next, in order to perform mold clamping, the first side mold 14 and the second side mold 16 slide on the upper end surface of the lower mold 12 along the arrow Y direction in FIGS. 1, 2, and 5. As a result, as shown in FIGS. 1 and 3, the baseboard portions 38 a and 38 b are accommodated in the holding recesses 50 of the first side mold 14 and the second side mold 16. As a result, the sand cores 22 a and 22 b are sandwiched between the baseboards 32 a and 32 b and the first side mold 14 or the second side mold 16.

  At substantially the same time as the sliding of the first side mold 14 and the second side mold 16, or after these sliding, the upper mold 18 is lowered so as to approach the lower mold 12, and the first side mold 14 and the second side mold 16 are moved. The mold is clamped in contact with. Along with this, a cavity 20 is formed (see FIG. 1).

  Next, molten aluminum alloy is introduced into the cavity 20. As the molten metal cools and solidifies (solidifies), a cylinder head is obtained. The cylinder head is formed with a combustion chamber corresponding to the shape of the combustion chamber forming portions 24a to 24d and a valve seat portion corresponding to the shape of the valve seat portion forming portions 26a to 26p, and a sand core 22a, A port for air supply / exhaust is formed by the port modeling portions 40a to 40p of 22b.

  Upon solidification, the cylinder head contracts with the outer edge toward the inside. At this time, if the port shaping portions 40a, 40c, 40n, and 40p are about to be displaced toward the inside of the lower mold 12, the second stopper surface 42 of the second stopper portion 44 becomes the valve seat portion forming portion 26a. , 26c, 26n, and 26p are dammed to the first stopper surface 28 of the first stopper portion 30. Thereby, it is prevented that the port shaping | molding part 40a, 40c, 40n, 40p raise | generates position shift.

  Similarly, when the port shaping portions 40f, 40h, 40i, 40k are about to be displaced toward the direction away from the baseboards 32a, 32b (inward of the lower mold 12), the fourth stopper portion 48 The fourth stopper surface 46 is blocked by the third stopper surface 34 of the third stopper portion 36 provided in the valve seat portion molding portions 26f, 26h, 26i, and 26k. Thereby, it is prevented that the port shaping | molding part 40f, 40h, 40i, 40k raise | generates position shift.

  As described above, the port modeling portions 40a, 40c, 40f, 40h, 40i, 40k, 40n, and 40p are positioned and fixed. For this reason, it becomes possible to set the port formed by these port shaping parts 40a, 40c, 40f, 40h, 40i, 40k, 40n, and 40p to a predetermined desired position.

  It should be noted that the port shaping portions 40b, 40d, 40e, 40g, 40j, 40l, 40m, and 40o rarely cause a positional deviation, and even if a positional deviation is caused, it is small enough to be ignored. Therefore, it is necessary to provide the first stopper portion 30 or the third stopper portion 36 in the valve seat portion forming portions 26b, 26d, 26e, 26g, 26j, 26l, 26m, and 26o, in other words, the port shaping portions 40b, 40d, There is no need to provide the second stopper portion 44 or the fourth stopper portion 48 at 40e, 40g, 40j, 40l, 40m, 40o.

  However, in order to further improve the position accuracy of the port, the second stopper portion 44 or the fourth stopper portion 48 may be provided in the port shaping portions 40b, 40d, 40e, 40g, 40j, 40l, 40m, and 40o. Of course. In this case, the second stopper portion 44 is provided in the port modeling portions 40b, 40d, 40m, and 40o positioned relatively outward in the parallel direction, and the port modeling portions 40e, 40g, and 40j positioned relatively inward in the parallel direction. , 40 l is preferably provided with a fourth stopper portion 48.

  After the cylinder head is solidified to such an extent that it can be taken out, the upper die 18 rises and the first side die 14 and the second side die 16 slide in a direction away from each other. Thereby, mold opening is made.

  As the mold opens, the cylinder head is exposed. In this cylinder head, a port is formed at a preset desired position. This is because the port modeling portions 40a to 40p are prevented from being displaced as described above.

  That is, the valve seat part molding parts 26a, 26c, 26n, and 26p are provided with the first stopper part 30, and the port shaping parts 40a, 40c, 40n, and 40p are provided with the second stopper part 44, and the valve seat part molding part 26f. 26h, 26i, 26k, the third stopper portion 36 is provided, and the port forming portions 40f, 40h, 40k, 40i are provided with the fourth stopper portion 48. A cylinder head formed in an ideal position / shape can be obtained. For this reason, it becomes easy to obtain desired engine characteristics.

  Further, the cylinder head is taken out from the lower mold 12. At this time, since the first stopper surface 28, the second stopper surface 42, the third stopper surface 34, and the fourth stopper surface 46 are inclined surfaces, the first stopper surface 28, the second stopper surface 42, and the third stopper surface. 34 and the fourth stopper surface 46 function as a so-called draft angle. The detachment of the cylinder head from the sand cores 22a and 22b proceeds promptly.

  In this case, a concave space for connecting the port shaping portions 40a to 40p is not formed in the cylinder head. Therefore, it is not necessary to remove the sand remaining in the concave space. Since the work process can be reduced by this amount, the cylinder head can be obtained efficiently.

  The present invention is not particularly limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

  For example, in this embodiment, the first stopper portion 30 is provided only in the valve seat portion molding portions 26a, 26c, 26n, and 26p located on the outermost side in the parallel direction, but the valve seat portion molding portion 26a is provided. The first stopper portion 30 may be provided in all of the .about.26p, and the second stopper portion 44 may be provided in all of the port shaping portions 40a to 40p. In this case, it is not particularly necessary to provide the third stopper portion 36 in the valve seat portion molding portions 26f, 26h, 26i, and 26k.

  Further, the position at which the first stopper portion 30 is provided is not necessarily the diameter position of the valve seat portion molding portions 26a, 26c, 26n, and 26p. As shown in FIG. The position may be biased to the side. Alternatively, as shown in FIG. 7, it may be a position deviated from the diameter position toward the inner side of the lower mold 12. The same applies to the third stopper portion 36.

DESCRIPTION OF SYMBOLS 10 ... Casting die apparatus 12 ... Lower die 14 ... 1st side type | mold 16 ... 2nd side type | mold 18 ... Upper type | mold 20 ... Cavity 22a, 22b ... Sand core 24a-24d for port formation ... Combustion chamber shaping | molding part 26a- 26p ... Valve seat portion molding portion 28 ... First stopper surface 30 ... First stopper portion 32a, 32b ... Baseboard 34 ... Third stopper surface 36 ... Third stopper portions 38a, 38b ... Baseboard portions 40a-40p ... Port Modeling part 42 ... 2nd stopper surface 44 ... 2nd stopper part 46 ... 4th stopper surface 48 ... 4th stopper part

Claims (5)

In a casting mold apparatus for obtaining a cylinder head having a combustion chamber,
A port-forming sand core comprising a plurality of port shaping portions for forming each of a plurality of ports communicating with the combustion chamber;
A mold comprising a baseboard for supporting the baseboard part of the port forming sand core;
Have
The mold is further formed to protrude from a bottom wall of a combustion chamber molding portion that molds the combustion chamber, and extends from the outer side to the inner side of the mold, and the extending direction of the baseboard portion A plurality of valve seat part forming parts facing each of the plurality of port shaping parts arranged substantially parallel to the
A portion of the upper end surface of the plurality of valve seat portion molding portions located on the outermost side in the parallel direction protrudes inward of the mold, as compared with other portions, so that the mold A first stopper portion having a surface facing the outer side of the mold is erected,
And the part which faces the outer side of the mold of the tip part of the plurality of port shaping parts located in the outermost direction in the parallel direction protrudes as compared with other parts, so that the first A casting mold apparatus, characterized in that a second stopper portion is provided to be opposed to the first stopper portion and blocked by the first stopper portion.   The mold apparatus according to claim 1, wherein the surface of the first stopper portion facing the outer side of the mold is inclined so as to rise from the outer side to the inner side of the mold. A mold apparatus for casting characterized by being a surface.   3. The mold apparatus according to claim 1, wherein the first stopper portion is provided only on the outermost side in the parallel direction among the plurality of valve seat portion molding portions, and the second stopper is provided. The casting mold apparatus is characterized in that the portion is provided only on the outermost portion in the parallel direction among the plurality of port shaping portions. The mold apparatus according to any one of claims 1 to 3, wherein an upper end surface of the plurality of valve seat part molding parts located in the middle part in the parallel direction is separated from the baseboard. The third stopper part having a surface facing the baseboard is erected by projecting the part of the second part compared to the other part,
And the part which faces the baseboard stand of the tip part of what is located in the parallel direction middle abdominal part among the plurality of port modeling parts protrudes compared with other parts, and it is in the 3rd stopper part. A casting mold apparatus, characterized in that a fourth stopper portion that is opposed to the third stopper portion is provided.   5. The mold apparatus according to claim 4, wherein the surface of the third stopper portion facing the baseboard is inclined so as to rise from a side close to the baseboard to a side away from the baseboard. A casting mold apparatus characterized by being.

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