JP6576063B2 - Sand core for forming intake port, manufacturing method thereof, and semi-finished product for cylinder head - Google Patents

Description

  The present invention relates to a sand core for forming an intake port, a manufacturing method thereof, and a semifinished product for a cylinder head for obtaining a cylinder head.

  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 an intake port and an exhaust port communicating with each combustion chamber. Further, the boundary between the combustion chamber and the intake port and the exhaust port is a valve seat portion in which a valve seat on which the cam valve is seated and separated is disposed.

  In this type of cylinder head, a metal partition member may be accommodated in the intake port and the intake port may be divided into a plurality of passages. In this case, since the vertical vortex (so-called tumble) is generated in the intake air introduced into the combustion chamber, the fluidity is increased, so that ignition is facilitated, and as a result, the engine performance is improved.

  The intake port is formed by an intake port forming sand core (hereinafter also simply referred to as “intake sand core”). The partition member is generally embedded in the port shaping portion of the intake sand core, but as described in Patent Document 1, a hollow portion is formed in the intake sand core, A partition member may be produced by introducing a molten metal for obtaining a cylinder head into the hollow portion and solidifying it. In this case, since it is not necessary to prepare a partition member separately, cost reduction can be achieved. Further, since it is not necessary to house the partition member in the core cavity for producing the sand core, the operation until the sand core is obtained is simplified.

Japanese Utility Model Publication No. 7-38665

  When a cylinder head is obtained, so-called low pressure casting is performed in which molten metal is introduced into the cylinder head cavity from below in the direction of gravity (vertical direction). That is, in this case, the liquid level of the molten metal rises along the vertical direction. On the other hand, in the cylinder head casting apparatus, the intake sand core is disposed such that the hollow portion is inclined with respect to gravity. That is, it is necessary to introduce the molten metal into the hollow portion in a direction different from the main hot water flow direction.

  However, it is not easy to cause the molten metal to flow in such a direction. After all, when it is intended to obtain a partition member by forming a hollow portion in the sand core for intake air, it is difficult for molten metal to flow into the hollow portion, and it is difficult to form a partition member having a desired shape. There is an inconvenience.

  The present invention has been made to solve the above-described problems, and it is easy to flow a molten metal into a hollow portion, and in some cases, a sand core for forming an intake port that can easily process a valve hole. And a manufacturing method thereof and a semi-finished product for a cylinder head.

In order to achieve the above object, the present invention provides a suction core forming sand core having a baseboard part and an intake port modeling part that projects from the baseboard part and models the intake port of a cylinder head,
In the intake port modeling part, a hollow part for modeling a partition member that partitions the intake port into a plurality of passages from a molten metal that obtains the cylinder head is formed,
The intake port forming sand core is disposed in the casting apparatus so that the hollow portion is in a direction intersecting the direction of gravity,
At least one of the first wall surface and the second wall surface facing each other in the hollow portion, in the vicinity of the entrance of the hollow portion, there are a plurality of inclined surfaces inclined in a direction away from the other wall surface facing the wall surface. It is formed.

Further, the present invention relates to a method for manufacturing a sand core for forming an intake port having a baseboard portion and an intake port forming portion that protrudes from the baseboard portion and forms an intake port of a cylinder head,
A step of accommodating the core for forming the hollow part in the core cavity of the sand core forming device;
Introducing sand into the core cavity and obtaining the intake port forming sand core having the intake port shaping portion and the baseboard portion;
Detaching the hollow portion forming core from the intake port modeling portion and forming a hollow portion for obtaining a partition member for partitioning the intake port into a plurality of passages in the intake port modeling portion;
Have
By forming an inclined surface on the hollow portion forming core, at least one of the first wall surface and the second wall surface facing each other in the hollow portion, in the vicinity of the inlet of the hollow portion, the other facing the wall surface A plurality of inclined surfaces that are inclined in a direction away from the wall surface are formed.

  When there are a plurality of inclined surfaces near the inlet of the molten metal in the hollow portion, the flow of the molten metal changes stepwise. For this reason, the inflow of the molten metal to the hollow portion becomes smooth. Moreover, by forming a plurality of inclined surfaces, the cross-sectional area of the hollow portion, that is, the cross-sectional area of the molten metal flow path is reduced stepwise. Therefore, it is possible to avoid the occurrence of vortex flow and pressure loss in the molten metal. Thereby, the casting quality of the partition member formed by the hollow portion becomes excellent.

  That is, in the intake port forming sand core (intake sand core) in which the hollow portion having the inclined surface as described above is formed, the hollow portion is the main hot water flow direction in the cylinder head cavity (for example, In spite of being inclined with respect to the gravity direction), the molten metal easily flows into the hollow portion. In other words, the hot water circulation is good. For this reason, it becomes easy to obtain a partition member having a predetermined shape as a high-quality one.

  The inclined surfaces are preferably formed on both the first wall surface and the second wall surface facing each other in the hollow portion. Here, the inclined surface is provided so as to be inclined from the parting portion of the hollow portion along the short-side direction and in a direction away from the opposing wall surface. Further, on one of the first wall surface and the second wall surface, a first inclined surface formed from a parting portion in a short direction of the hollow portion and a second inclined surface formed continuously to the first inclined surface are provided. One of the provided and remaining portions is provided with a third inclined surface formed from a parting portion in the short direction of the hollow portion. By forming the first to third inclined surfaces in this way, the hot water circulation to the hollow portion is further improved.

  In order to make the hot water supply even better, it is preferable to set the length direction dimension of the first inclined surface along the short direction of the hollow portion to be shorter than that of the third inclined surface. Note that the sum of the lengthwise dimensions of the first inclined surface and the second inclined surface along the short direction of the hollow portion may be longer or shorter than the third inclined surface. Also good.

  It is also preferable to set the inclination angle of the second inclined surface to be larger than that of the first inclined surface and the third inclined surface because the hot water supply is further improved.

  In order to further improve the hot water circulation, the hollow portion may be formed in a shape in which the partition member is thick on the combustion chamber side and thin on the baseboard side. Alternatively, the partition member may be formed to be thin on the combustion chamber side and thick on the baseboard side.

  In any case, it is preferable to form the plurality of inclined surfaces on the wall surface of the first wall surface or the second wall surface that is close to the gate of the casting apparatus. By forming a plurality of inclined surfaces on the wall surface where the molten metal reaches first, the molten metal can be smoothly introduced into the hollow portion. Therefore, the casting quality of the partition member is improved.

  And forming the 1st recessed part or 1st convex part for forming the convex part for a process parameter | index or the recessed part for a process parameter | index on the said partition member in the wall surface which faces upwards among a 1st wall surface or a 2nd wall surface. preferable.

  In this case, when the valve hole is formed in the cylinder head, the processing index convex portion or the processing index concave portion formed in the partition member by the transfer of the first concave portion or the first convex portion can be used as the processing index. That is, the machining tool is entered with the machining index as a target, and is brought into contact with the partition member. Thereby, it can avoid that the advancing direction of the processing tool changes.

  The machining tool then passes through the partition member, reaches the wall of the cylinder head semi-finished product, and forms a valve hole. Since the change of the traveling direction of the machining tool is avoided, the valve hole can be formed to extend in a desired direction designed in advance. Therefore, the valve hole can be easily formed, and an internal combustion engine including the cylinder head can be obtained as exhibiting desired engine characteristics.

  Furthermore, it is preferable to form a second concave portion or a second convex portion for providing a rectifying convex portion or a rectifying concave portion on the partition member on at least one of the first wall surface and the second wall surface. In this case, it is because the intake air is efficiently performed in the internal combustion engine by forming the rectifying convex portion or the rectifying concave portion in the partition member.

Further, the present invention provides a cylinder head semi-product for obtaining a cylinder head in which an intake port is formed.
A partition member for partitioning the intake port into a plurality of passages is inserted into the intake port,
A plurality of inclined surfaces inclined toward the other surface are formed on at least one of the lower surface and the upper surface of the partition member.

  That is, in this cylinder head semi-finished product, a partition member having a shape corresponding to the shape of the hollow portion is formed. This is because the hot water around the hollow portion is good as described above.

  Furthermore, it is preferable to form a concave portion or a convex portion for a processing index on the lower surface of the end portion on the combustion chamber side of the partition member. In this case, the valve hole can be easily formed in a desired shape by using the concave portion of the partition member existing in the intake port as a processing index. That is, a cylinder head can be obtained efficiently.

  As described above, by using the recess formed in the partition member as a processing index and causing the machining tool to advance into the recess, a valve hole extending in a desired direction can be easily formed. As a result, an internal combustion engine exhibiting excellent engine characteristics can be obtained.

  In addition to the above configuration, a rectifying convex portion or a rectifying concave portion may be formed on at least one of the lower surface and the upper surface of the partition member. With this configuration, intake is efficiently performed in the internal combustion engine.

  According to the present invention, in the vicinity of the inlet of the hollow portion for forming the partition member formed in the intake port forming portion of the intake port forming sand core (intake sand core) and partitioning the intake port into a plurality of passages. A plurality of inclined surfaces are formed. For this reason, the molten metal easily flows into the hollow portion. That is, since the hot water circulation is good, a partition member having a desired shape can be easily obtained.

It is a schematic side sectional view of an intake port forming sand core (intake sand core) according to an embodiment of the present invention. It is the II-II arrow directional cross-sectional view in FIG. It is principal part side surface sectional drawing of the sand core shaping | molding apparatus for shape | molding the sand core for intake shown in FIG. It is a front principal part sectional view which shows the state by which the hollow part formation core (1st division piece and 2nd division piece) which comprises the said sand core shaping | molding apparatus was embedded in the intake port modeling part. It is a principal part schematic longitudinal cross-sectional view of the casting apparatus comprised including the sand core for intake shown in FIG. It is a typical front principal part longitudinal cross-sectional view of the semifinished product for cylinder heads obtained by the casting apparatus of FIG. It is a typical front principal part longitudinal cross-sectional view of the cylinder head obtained from the semi-finished product of FIG. It is a principal part longitudinal cross-sectional view of the sand core for intake which makes another shape. It is a principal part longitudinal cross-sectional view of the sand core for intake which makes another shape. It is principal part side surface sectional drawing of the sand core shaping | molding apparatus which has a hollow part formation core for obtaining the sand core for intake which makes another shape. It is XI-XI arrow sectional drawing in FIG. It is XII-XII arrow directional cross-sectional view in FIG. It is XIII-XIII sectional view taken on the line in FIG. It is a schematic principal part side surface sectional drawing of the partition member in which the convex part for rectification | straightening was formed.

  Hereinafter, an intake port forming sand core (intake sand core) according to the present invention is preferably implemented in relation to a manufacturing method thereof and a semifinished product for a cylinder head obtained using the intake sand core. And will be described in detail with reference to the accompanying drawings. In the following, the cylinder head semi-finished product and the exhaust port forming sand core may be simply referred to as “semi-finished product” and “exhaust sand core”, respectively.

  FIG. 1 is a schematic side cross-sectional view of an intake sand core 10 according to the present embodiment. The intake sand core 10 includes an intake port shaping portion 12 (so-called product portion) for forming an intake port, and a baseboard portion 14 that is not involved in forming the cylinder head.

  The intake port modeling portion 12 protrudes from the baseboard portion 14 and is slightly curved along the horizontal direction, and then has a shape that is also slightly curved downward. On the other hand, a first engagement portion (not shown) is formed on the baseboard portion 14 having a substantially rectangular parallelepiped shape.

  A long hollow portion 16 is formed in the sand core 10 for intake air from the combustion chamber side end portion of the intake port modeling portion 12 to the baseboard portion 14. The hollow portion 16 is for forming the tumble plate 18 (partition member) shown in FIG. The tumble plate 18 will be described later.

  The hollow portion 16 is a so-called horizontal groove that opens on the side surface of the intake port modeling portion 12. Therefore, the bottom wall 19 and the ceiling wall 20 are formed in the hollow portion 16 as a first wall surface and a second wall surface facing each other. In the present embodiment, the separation distance between the bottom wall 19 and the ceiling wall 20 is set to be large at the combustion chamber side end and small at the baseboard side end.

  Further, in the bottom wall 19, a concave portion forming convex portion 22 for forming a processing index concave portion 21 (see FIG. 6) is provided at the end portion on the combustion chamber side as a substantially rectangular parallelepiped shape. That is, the concave portion forming convex portion 22 is formed in a spot shape and is not long.

  As shown in FIG. 2, which is a cross-sectional view taken along the line II-II in FIG. 1, the bottom wall 19 and the ceiling wall 20 are laterally open (outward) ) In the direction of separating from each other. In other words, the hollow portion 16 expands from the parting portions P1 and P2 in the short direction toward the side openings.

  The bottom wall 19 is connected to each of the first inclined surfaces 24a and 24b which are gently inclined so as to go downward from the parting portion P1 in the short direction toward the side opening, and the first inclined surfaces 24a and 24b. The second inclined surfaces 26a and 26b are steeply inclined so as to be directed downward toward the side opening side. That is, a plurality of inclined surfaces including the first inclined surface 24a and the second inclined surface 26a are formed in the vicinity of one inlet of the molten metal, and the first inclined surface 24b and the second inclined surface 26b are formed in the vicinity of the other inlet. A plurality of inclined surfaces are formed.

  In this embodiment, when the length of each of the first inclined surfaces 24a and 24b is La and the length of each of the second inclined surfaces 26a and 26b is Lb, the short side of the hollow portion 16 of the bottom wall 19 is used. The length TL1 along the direction is 2 × (La + Lb). Further, a relationship of La> Lb is established.

  On the other hand, the ceiling wall 20 includes third inclined surfaces 28a and 28b that are gently inclined so as to be directed upward from the parting portion P2 in the short direction toward the side opening side. When the length of each of the third inclined surfaces 28a, 28b is Lc, the length TL2 of the ceiling wall 20 along the short direction of the hollow portion 16 is 2 × Lc.

As shown in FIG. 2, La is set smaller than Lc, and La + Lb is set larger than Lc. That is, each of the first inclined surfaces 24a and 24b is shorter than the third inclined surfaces 28a and 28b, and the total length of the first inclined surfaces 24a (24b) and the second inclined surfaces 26a (26b) is the third. Larger than the inclined surface 28a (28b). After all, the following relational expression holds.
La <Lc
La + Lb> Lc (TL1> TL2)

  The first inclined surfaces 24a and 24b are preferably inclined at 5 ° or less with respect to the horizontal direction. That is, the preferable inclination angle θ1 of the first inclined surfaces 24a and 24b is 5 ° or less. The inclination angle θ1 is more preferably 2 ° or less, and is typically between 1 ° and 2 °.

  The second inclined surfaces 26a and 26b are inclined with respect to the horizontal direction preferably at 25 ° or less, more preferably at 20 ° or less. That is, the preferable inclination angle θ2 of the second inclined surfaces 26a and 26b is 25 ° or less, more preferably 20 ° or less. The inclination angle θ2 is set larger than the inclination angle θ1.

  The inclination angle θ3 of the third inclined surfaces 28a and 28b may be approximately the same as that of the first inclined surfaces 24a and 24b. That is, the inclination angle θ3 of the third inclined surfaces 28a and 28b is preferably 5 ° or less, and more preferably 2 ° or less. Typically, it may be 1 ° to 2 °.

  Next, a method for manufacturing the intake sand core 10 will be described. FIG. 3 is a side sectional view of a main part of the sand core forming apparatus 30. The sand core molding apparatus 30 includes a core lower mold 32, a core upper mold 34 disposed above the core lower mold 32, and a plurality of core side molds (not shown). And have. The lower core mold 32 is a fixed mold, while the upper core mold 34 is movable so as to approach (lower) or separate (up) from the lower core mold 32 under the action of a lifting mechanism (not shown). It is a type. The side mold for the core is a so-called sliding type in which the core cavity 36 is formed together with the core lower mold 32 and the core upper mold 34.

  A blow port 38 for introducing sand particles into the core cavity 36 is formed in the vicinity of the mating surface of the core lower mold 32 and the core upper mold 34. The core cavity 36 accommodates a hollow portion forming core 40 for forming the hollow portion 16 in the intake port modeling portion 12. That is, the shape of the hollow portion forming core 40 corresponds to the shape of the hollow portion 16.

  As shown in FIG. 4, the hollow portion forming core 40 includes a first divided piece 42a and a second divided piece 42b. For example, the first divided piece 42a is supported by the side mold for the core disposed on the back side of the sheet of FIG. 3, while the second divided piece 42b is the side for the core disposed on the front side of the sheet. Supported by the mold. That is, the first divided piece 42a and the second divided piece 42b move integrally with the core side mold. Since the side mold for the core moves along the horizontal direction, the first divided piece 42a and the second divided piece 42b also move along the horizontal direction. A part of the first divided piece 42 a and the second divided piece 42 b may be sandwiched between the core lower mold 32 and the core upper mold 34.

  The thickness of the first divided piece 42a and the second divided piece 42b is set to be large at the combustion chamber side end and small at the baseboard part side end. In addition, inclined surfaces 43a and 43b corresponding to the first inclined surface 24a and the second inclined surface 26a of the bottom wall 19 of the hollow portion 16 are formed on the lower surface of the first divided piece 42a, and the upper surface is hollow. An inclined surface 43c corresponding to the third inclined surface 28a of the ceiling wall 20 of the portion 16 is formed. Similarly, inclined surfaces 43d and 43e corresponding to the first inclined surface 24b and the second inclined surface 26b are formed on the lower surface of the second divided piece 42b, and an inclined surface corresponding to the third inclined surface 28b is formed on the upper surface. 43f is formed.

  Furthermore, the 1st division | segmentation recessed part 44a and the 2nd division | segmentation recessed part 44b are each formed in each combustion chamber side front-end | tip of the 1st division | segmentation piece 42a and the 2nd division | segmentation piece 42b. The first divided concave portion 44a and the second divided concave portion 44b are in positions facing each other. Therefore, when the first divided piece 42a and the second divided piece 42b come into contact with each other, the first divided concave portion 44a and the second divided concave portion 44b are connected. . Thereby, the concave part 46 for shaping | molding the said convex part 22 for recessed part formation (refer FIG. 1) as a 1st convex part is formed.

  When the mold is closed, the first and second divided pieces 42a and 42b come close to each other and come into contact with each other as the two opposite side molds for the core approach each other (see FIG. 4). . As a result, the hollow portion forming core 40 is formed in the core cavity 36 (see FIG. 3).

  Next, sand particles containing the binder are supplied to the core cavity 36 through the blow port 38. The sand particles surround the hollow portion forming core 40 and fill the core cavity 36. The sand particles are aggregated by receiving a compressive force, and the sand particles are bonded to each other by the binder, whereby the intake sand core 10 as a solid molded body is formed.

  Next, mold opening is performed. At this time, the two core side molds facing each other are displaced in directions away from each other. Following this, the first divided piece 42a and the second divided piece 42b are separated from each other and separated from the intake port modeling portion 12 of the intake sand core 10. This separation mark becomes the hollow portion 16. That is, the intake sand core 10 having the intake port shaping portion 12 and the baseboard portion 14 and having the hollow portion 16 is exposed.

  Based on the shape of the hollow portion forming core 40, the separation distance between the bottom wall 19 and the ceiling wall 20 of the hollow portion 16 is large at the combustion chamber side end portion and is small at the baseboard portion side end portion. Further, the first inclined surfaces 24 a and 24 b and the second inclined surfaces 26 a and 26 b are formed on the bottom wall 19, and the third inclined surfaces 28 a and 28 b are formed on the ceiling wall 20. Further, the concave portion forming convex portion 22 corresponding to the shape of the molding concave portion 46 is provided at the combustion chamber side end portion of the intake port modeling portion 12 in the hollow portion 16. In addition, a first engagement portion (not shown) is formed in the baseboard portion 14.

  Next, the semi-finished product 90 (see FIG. 6) will be described in relation to the casting apparatus 50 shown in FIG. The casting apparatus 50 has a cylinder head lower mold 52, a sliding-type first side mold 54 and second side mold 56, and a cylinder head upper mold 58 as molds. The cylinder head cavity 60 is formed by the cylinder head lower mold 52, the first side mold 54, the second side mold 56, and the cylinder head upper mold 58. The intake sand core 10 includes an exhaust port forming sand core (exhaust sand core) 62 and a cavity forming sand core 63 for forming a cavity in the cylinder head 102 (see FIG. 7). It arrange | positions in the cavity 60 for cylinder heads.

  This casting apparatus 50 is for obtaining the cylinder head 102 by casting, and the shape of the cylinder head cavity 60 corresponds to the shape of the cylinder head 102 (semi-finished product 90). That is, a predetermined number (for example, four) of combustion chamber forming portions 64 for forming the combustion chamber 92 of the cylinder head 102 is formed in the cylinder head lower mold 52. The combustion chamber forming portions 64 are arranged in parallel along the longitudinal direction of the cylinder head lower mold 52 (the direction perpendicular to the paper surface of FIG. 5).

  In one combustion chamber forming portion 64, for example, two valve seat portion forming portions 66 for providing a valve seat portion in the cylinder head 102 are provided. The individual valve seat portion forming portions 66 protrude from the upper surface of the combustion chamber forming portion 64 toward the intake sand core 10 and the exhaust sand core 62.

  On the upper surface of the lower cylinder head mold 52, baseboards 68a and 68b are formed so as to project vertically upward. These baseboards 68a and 68b extend along the longitudinal direction of the cylinder head lower mold 52 (direction perpendicular to the paper surface of FIG. 5).

  The skirting boards 68a and 68b are respectively provided with second engaging portions (not shown). Each second engaging portion is engaged with the first engaging portion of the baseboard portion 72 of the sand core 62 for exhaust and the first engaging portion of the baseboard portion 14 of the sand core 10 for intake. The exhaust sand core 62 and the intake sand core 10 are supported by the baseboards 68a and 68b.

  The first side mold 54 and the second side mold 56 slide on the upper surface of the cylinder head lower mold 52 under the action of a driving mechanism (for example, a hydraulic cylinder) (not shown). The sliding direction is the arrow Y direction in FIG.

  The first side mold 54 and the second side mold 56 have holding recesses 78 and 80 that can be fitted into the baseboard portion 14 of the intake sand core 10 and the baseboard portion 72 of the exhaust sand core 62, respectively. It is formed. In other words, the holding recesses 78 and 80 are fitted into the baseboard parts 14 and 72 during mold clamping.

  The cylinder head upper mold 58 is lowered or raised so as to be relatively close to or separated from the cylinder head lower mold 52 under the action of an unillustrated lifting mechanism (for example, a hydraulic cylinder). Of course, the mold is closed as it descends, and as a result, the cylinder head cavity 60 is formed. On the other hand, the mold is opened by raising.

  Next, the effect of the intake sand core 10 according to the present embodiment will be described in relation to the casting method of the cylinder head 102.

  Prior to obtaining the semi-finished product 90, the baseboard part 14 of the sand core 10 for intake and the baseboard part 72 of the sand core 62 for exhaust are respectively supported by the baseboards 68 b and 68 a of the lower die 52 for cylinder head. To do. As described above, at this time, the first engaging portions of the baseboards 68b and 68a are engaged with the second engaging portions of the baseboard portions 14 and 72, respectively. As a result, the intake sand core 10 and the exhaust sand core 62 are positioned and are prevented from falling off the baseboards 68b and 68a.

  As the positioning is performed, the front end of the combustion chamber side end portion of the intake port shaping portion 12 of the intake sand core 10 is seated at a predetermined portion of the valve seat portion forming portion 66. Similarly, the tip of the combustion chamber side end portion of the exhaust port shaping portion 76 of the exhaust sand core 62 is seated at another predetermined portion of the valve seat portion forming portion 66.

  Next, in order to perform mold clamping, the first side mold 54 and the second side mold 56 slide on the upper surface of the cylinder head lower mold 52 along the arrow Y direction in FIG. As a result, as shown in FIG. 5, the baseboard parts 14 and 72 are accommodated in the holding recesses 78 and 80 of the second side mold 56 and the first side mold 54. As a result, the exhaust sand core 62 is sandwiched between the baseboard 68 a and the first side mold 54, and the intake sand core 10 is sandwiched between the baseboard 68 b and the second side mold 56.

  The cylinder head upper mold 58 is lowered so as to approach the cylinder head lower mold 52 substantially simultaneously with or before and after the sliding of the first side mold 54 and the second side mold 56, and the first side mold 54 and The mold is closed in contact with the second side mold 56. Along with this, a cylinder head cavity 60 is formed.

  Next, a molten aluminum alloy is introduced into the cylinder head cavity 60 from the cylinder head lower mold 52 side. That is, the molten metal is introduced from below the cylinder head cavity 60, and the liquid level rises as the introduction proceeds. The opening serving as the molten metal inlet of the hollow portion 16 is formed on the side of the intake port modeling portion 12, and is therefore inclined with respect to the direction of gravity, which is the liquid level rising direction.

  Here, as shown in FIG. 2, the bottom wall 19 of the hollow portion 16 has the first inclined surfaces 24a and 24b and the second inclined surfaces 26a and 26b, and the ceiling wall 20 has the third inclined surface. Since 28a and 28b are formed, they are inclined so as to expand from the parting parts P1 and P2 in the short direction toward the side openings, respectively. In addition, the relationship of La <Lc, La + Lb> Lc (TL1> TL2) is established, and the inclination angle θ2 of the second inclined surfaces 26a, 26b is larger than the inclination angle θ1 of the first inclined surfaces 24a, 24b. Furthermore, the separation distance between the bottom wall 19 and the ceiling wall 20 is set so as to increase from the end of the baseboard portion toward the end of the combustion chamber.

  For the reasons described above, the molten metal easily flows into the hollow portion 16 even though the opening of the hollow portion 16 intersects the liquid level rising direction. That is, the hot water around the hollow portion 16 is good. For this reason, it becomes easy to obtain the tumble plate 18 having a shape corresponding to the shape of the hollow portion 16.

  As the molten metal cools and solidifies, a semi-finished product 90 shown in FIG. 6 is obtained as a solidified product. 5 and 6 schematically show the main part for convenience of explanation. For this reason, there is a part where the shape of the cylinder head cavity 60 and the shape of the semi-finished product 90 do not match. The same applies to the cylinder head 102 shown in FIG.

  In the semi-finished product 90, a combustion chamber 92 corresponding to the shape of the combustion chamber forming portion 64 is formed. As the cylinder head upper mold 58 rises and the first side mold 54 and the second side mold 56 slide in a direction away from each other, the mold is opened and the semi-finished product 90 is exposed. Further, by collapsing the intake sand core 10 and the exhaust sand core 62, the intake port 94 and the exhaust port 96 appear as spaces.

  Further, the tumble plate 18 having a shape corresponding to the shape of the hollow portion 16 is formed in the intake port 94 as described above. On the lower surface of the end portion on the combustion chamber side of the tumble plate 18, a processing index recess 21 corresponding to the shape of the forming recess 46 is recessed so as to face the upper surface side of the tumble plate 18. In this case, the processing index recess 21 is formed in a dot shape.

  Then, in order to obtain the cylinder head 102 (see FIG. 7) from the semi-finished product 90, the intake valve hole 98 and the exhaust valve hole 100 are formed. That is, a machining tool is inserted from below the semi-finished product 90 to perform drilling.

  Here, at the end of the tumble plate 18 on the combustion chamber side, there is a processing index recess 21. The operator may insert the machining tool along the arrow direction shown in FIG. 6 using the machining index recess 21 as an index. The machining tool easily proceeds into the machining index recess 21 of the tumble plate 18. Thereafter, the machining tool passes through the ceiling wall of the machining index recess 21 and further proceeds in the direction of the arrow. The machining tool grinds or cuts the inner wall of the intake valve hole 98 to finish the intake valve hole 98 to a predetermined size.

  Eventually, the processing index recess 21 is located on the same axis as the processing portion for forming the intake valve hole 98. Therefore, the intake valve hole 98 can be easily formed by using the processing index recess 21 formed at the end of the tumble plate 18 on the combustion chamber side as an index. In addition, since the machining tool advances in the machining index recess 21, the fear that the machining tool is displaced from the direction in which it should proceed is eliminated. Therefore, the intake valve hole 98 can be extended along a desired direction.

  Further, since the combustion chamber side end portion of the tumble plate 18 is simultaneously processed by the processing tool, the processing tool interferes with the tumble plate 18 so that the formation of the intake valve hole 98 does not become difficult. .

  Furthermore, since the tumble plate 18 can be formed using the molten metal for obtaining the semi-finished product 90 (cylinder head 102), it is necessary to prepare the tumble plate 18 separately prepared to produce the intake sand core 10. There is no. Accordingly, there is an advantage that the cost can be reduced, and the work until the intake sand core 10 is obtained is simplified.

  In order to obtain the cylinder head 102 shown in FIG. 7, separately produced valve seats 104 and 106 are press-fitted into a portion formed by the valve seat portion forming portion 66. On the other hand, the stem guides 108 and 110 are press-fitted into the intake valve hole 98 and the exhaust valve hole 100 that have been finished. The stem of the intake valve 112 is slidably inserted into the stem guide 108, while the stem of the exhaust valve 114 is slidably inserted into the stem guide 110. As the camshaft 116 rotates, the umbrella portion of the intake valve 112 is seated or separated from the valve seat 104, and the umbrella portion of the exhaust valve 114 is separated or seated from the valve seat 106.

  Further, as described above, the tumble plate 18 having a shape corresponding to the shape of the hollow portion 16 remains in the intake port 94. The tumble plate 18 divides the intake port 94 into two passages. In the internal combustion engine including the cylinder head 102 having the tumble plate 18, when the intake air is introduced into the combustion chamber 92, a vertical vortex is generated in the intake air. As a result, the fluidity of the intake air increases, which improves engine performance.

  As shown in FIG. 8, the sand core 120 for intake may be manufactured by setting the dimension in the width direction of the ceiling wall 20 to be larger than that of the bottom wall 19. Even in this case, it is preferable to form the first inclined surfaces 24 a and 24 b and the second inclined surfaces 26 a and 26 b on the bottom wall 19 and to form the third inclined surfaces 28 a and 28 b on the ceiling wall 20. In this case, since the rising molten metal is received by the wide ceiling wall 20, it is expected that the hot water around the hollow portion 16 is further improved.

  Further, as shown in FIG. 9, an intake sand core 122 in which the bottom wall 19 and the ceiling wall 20 are inclined from one side opening to the other side opening may be used. In this case, a first inclined surface 24 a and a second inclined surface 26 a are formed on the bottom wall 19, and a third inclined surface 28 a is formed on the ceiling wall 20.

  Furthermore, instead of the hollow portion forming core 40 in which the forming concave portion 46 is formed, a hollow portion forming core 132 in which the forming convex portion 130 shown in FIG. 10 is formed may be used. In this case, as shown in FIG. 11 which is a cross-sectional view taken along the line XI-XI in FIG. 10, the forming convex portion 130 is formed as a belt-like convex portion extending from one side surface to the other side surface of the hollow portion forming core 132. Is done. Moreover, the shape of the hollow portion forming core 132 is as shown in FIG. 12, which is a cross-sectional view taken along line XII-XII in FIG. 11 and FIG. 10, and FIG. 13 which is a cross-sectional view taken along line XIII-XIII. Change.

  In this case, a concave portion for forming a convex portion (first concave portion) is formed on the lower surface of the sand core for intake air.

  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, the tumble plate 18 may have a shape that is thin at the combustion chamber side end and thick at the baseboard side end.

  Moreover, as shown in FIG. 14, you may make it form the convex part 140 for a rectification | straightening in the lower surface or upper surface of the tumble board 18, Preferably both. For this purpose, by forming the original convex part on the hollow part forming core 40 (or the hollow part forming core 132), the original part is formed on the bottom wall 19 or the ceiling wall 20 of the hollow part 16, preferably both. A transfer concave portion to which the shape of the convex portion is transferred is formed. The rectifying convex portion 140 is formed based on the transfer concave portion.

  Instead of the rectifying convex portion 140, a rectifying concave portion may be formed. In this case, the original concave portion is formed in the hollow portion forming core 40 (or the hollow portion forming core 132). As a result, a transfer convex portion in which the shape of the original concave portion is transferred is formed on the bottom wall 19 or the ceiling wall 20 of the hollow portion 16, preferably both, and the rectifying concave portion is further formed on the basis of the transfer convex portion. Molded.

  In any case, in the internal combustion engine including the cylinder head 102, intake can be performed more efficiently.

DESCRIPTION OF SYMBOLS 10, 120, 122 ... Sand core for intake 12 ... Intake port shaping | molding part 14, 72 ... Baseboard part 16 ... Hollow part 18 ... Tumble board 19 ... Bottom wall 20 ... Ceiling wall 21 ... Concave part 22 for process parameter | index ... Recess formation Convex part 24a, 24b ... 1st inclined surface 26a, 26b ... 2nd inclined surface 28a, 28b ... 3rd inclined surface 30 ... Sand core forming apparatus 32 ... Core lower mold 34 ... Core upper mold 36 ... Cavities 40, 132 for cores 42a, 42b ... Split pieces 44a, 44b ... Split recesses 46 ... Molding recesses 50 ... Casting device 52 ... Cylinder head lower die 54 ... First side die 56 ... Second side mold 58 ... Cylinder head upper mold 60 ... Cylinder head cavity 62 ... Exhaust sand core 68a, 68b ... Skirting board 76 ... Exhaust port shaping part 90 ... Cylinder head semi-finished product 92 ... Combustion chamber 94 ... Intake port 96 Exhaust port 98 ... Intake valve hole 100 ... Exhaust valve hole 102 ... Cylinder head 140 ... Rectification convex part

Claims (21)

In the suction port forming sand core having a baseboard portion and an intake port forming portion that protrudes from the baseboard portion and forms an intake port of the cylinder head,
In the intake port modeling part, a hollow part for modeling a partition member that partitions the intake port into a plurality of passages from a molten metal that obtains the cylinder head is formed,
The intake port forming sand core is disposed in the casting apparatus so that the hollow portion is in a direction intersecting the direction of gravity,
The hollow part has an opening on each of two opposing side surfaces of the intake port modeling part,
One of the first wall surface and the second wall surface facing each other in the hollow portion is adjacent to each other and inclined near the at least one of the two opening portions with respect to the short direction of the hollow portion. It has a plurality of inclined surfaces with different angles,
The intake port forming sand core, wherein the plurality of inclined surfaces are inclined toward the opening so as to be separated from the other of the first wall surface and the second wall surface. 2. The sand core according to claim 1, wherein both the first wall surface and the second wall surface are along a lateral direction from the parting portion of the hollow portion and away from the other wall surface facing the wall surface. Tilt to
On one of the first wall surface and the second wall surface, there are a first inclined surface formed from a parting portion in a short direction of the hollow portion, and a second inclined surface formed continuously to the first inclined surface. Provided,
And the 3rd inclined surface formed from the parting part of the transversal direction of the said hollow part is provided in one side of the remainder, The sand core for intake port formation characterized by the above-mentioned.   3. The sand core according to claim 2, wherein a length dimension of the first inclined surface along a short direction of the hollow portion is shorter than that of the third inclined surface. Sand core.   The sand core for forming an intake port according to claim 2 or 3, wherein an inclination angle of the second inclined surface is larger than that of the first inclined surface and the third inclined surface. .   5. The sand core according to claim 1, wherein the hollow portion is formed in a shape in which the partition member is thick on the combustion chamber side and the baseboard portion side is thin. A sand core for forming intake ports.   The sand core according to any one of claims 1 to 4, wherein the hollow portion is formed in a shape in which the partition member is thin on the combustion chamber side and the baseboard portion side is thick. A sand core for forming intake ports.   The sand core according to any one of claims 1 to 6, wherein the plurality of inclined surfaces are formed on a wall surface of the first wall surface or the second wall surface that is close to a gate of the casting apparatus. A sand core for forming an intake port.   In the sand core according to any one of claims 1 to 7, a processing index convex portion or a processing index concave portion is provided on the partition member on a wall surface facing the upper side of the first wall surface or the second wall surface. A sand core for forming an intake port, wherein a first concave portion or a first convex portion for forming the air port is formed.   The sand core according to any one of claims 1 to 8, wherein at least one of the first wall surface and the second wall surface is provided with a rectifying convex portion or a rectifying concave portion on the partition member. A sand core for forming an intake port, wherein the second concave portion or the second convex portion is formed. In a manufacturing method of a sand core for forming an intake port having a baseboard part and an intake port forming part that protrudes from the baseboard part and forms an intake port of a cylinder head,
A step of accommodating the core for forming the hollow part in the core cavity of the sand core forming device;
Introducing sand into the core cavity and obtaining the intake port forming sand core having the intake port shaping portion and the baseboard portion;
Detaching the hollow portion forming core from the intake port modeling portion and forming a hollow portion for obtaining a partition member for partitioning the intake port into a plurality of passages in the intake port modeling portion;
Have
The hollow part has an opening on each of two opposing side surfaces of the intake port modeling part,
By forming an inclined surface in the hollow portion forming core, one of the first wall surface and the second wall surface facing each other in the hollow portion is disposed in the vicinity of at least one of the two opening portions. Forming a plurality of inclined surfaces that are inclined with respect to the short direction, are adjacent to each other and have different inclination angles,
The method of manufacturing a sand core for forming an intake port, wherein the plurality of inclined surfaces are inclined toward the opening so as to be separated from the other of the first wall surface and the second wall surface. The manufacturing method according to claim 10, wherein both the first wall surface and the second wall surface are separated from the other wall surface facing the wall surface so as to extend along the short direction from the parting portion of the hollow portion. Forming an inclined surface,
On one of the first wall surface or the second wall surface, a first inclined surface formed from a parting portion in a short direction of the hollow portion and a second inclined surface connected to the first inclined surface are formed,
In addition, the third inclined surface is formed on the remaining one side from the parting portion in the short direction of the hollow portion.   The manufacturing method according to claim 11, wherein the first inclined surface is formed such that a lengthwise dimension along a short direction of the hollow portion is shorter than that of the third inclined surface. A method of manufacturing a sand core for forming an intake port.   The manufacturing method according to claim 11 or 12, wherein an inclination angle of the second inclined surface is set to be larger than that of the first inclined surface and the third inclined surface. Child manufacturing method.   The manufacturing method according to any one of claims 11 to 13, wherein the hollow portion is formed in a shape in which the partition member is thick on the combustion chamber side and the baseboard portion side is thin. A method of manufacturing a sand core for forming an intake port.   The manufacturing method according to any one of claims 11 to 13, wherein the hollow portion is formed in a shape in which the partition member is thin on the combustion chamber side and the baseboard portion side is thick. A method of manufacturing a sand core for forming an intake port.   The manufacturing method according to any one of claims 11 to 15, wherein the plurality of inclined surfaces are formed on a wall surface of the first wall surface or the second wall surface that is close to a gate of a casting apparatus. A method for producing a sand core for forming an intake port.   The manufacturing method according to any one of claims 11 to 16, wherein at least one of the first wall surface and the second wall surface is formed with a convex portion or a concave portion for a processing index. A method for producing a sand core for port formation.   The manufacturing method according to any one of claims 11 to 17, wherein an original convex portion or an original concave portion is formed on the hollow portion forming core, and at least one of the first wall surface and the second wall surface. A method for producing a sand core for forming an intake port, wherein a concave portion for transfer to which the shape of the original convex portion is transferred or a convex portion for transfer to which the shape of the original concave portion is transferred is formed. In a semi-finished product for a cylinder head for obtaining a cylinder head having an intake port,
A partition member for partitioning the intake port into a plurality of passages is inserted into the intake port,
One of the lower surface and the upper surface of the partition member, in the vicinity of at least one of both ends in the short direction of the partition member, are inclined with respect to the short direction of the partition member, are adjacent to each other, and have different inclination angles. A plurality of inclined surfaces are formed,
The semi-finished product for a cylinder head, wherein the plurality of inclined surfaces are inclined so as to be separated from the other of the lower surface and the upper surface toward one end of the partition member in the short direction.   21. The semifinished product for a cylinder head according to claim 19, wherein a concave portion or a convex portion for a processing index is formed on a lower surface of a combustion chamber side end portion of the partition member.   21. The semifinished product for a cylinder head according to claim 19 or 20, wherein a rectifying convex portion or a rectifying concave portion is formed on at least one of the lower surface and the upper surface of the partition member.

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