JPS62282746A - Expendable pattern for casting cylinder head for internal combustion engine - Google Patents

Abstract

PURPOSE:To eliminate the waste metal of a cylinder head and to improve the cooling characteristic thereof by dividing an expendable pattern for casting the cylinder head by the parting lines running the junctures between ignition plug mounting parts and combustion chamber wall and running above suction and exhaust ports. CONSTITUTION:The cylinder head 11 is set with the parting line D, E, F, G, H extending horizontally from a suction side lateral face 22 toward an exhaust side lateral face 23 to form the respective expendable patterns corresponding to divided blocks 101, 102, 103, 104, 105, 106. The ignition plug mounting parts 12 and the combustion chamber wall 43 forming the base of a water jacket 19e are integrally connected in this stage so that the corresponding expendable patterns are formed across the blocks 104, 105, 106 and are divided in the posi tion of the parting line D. Fitting parts for registration are provided to the parting planes of the respective expendable patterns and the patterns are united to one body by an adhesive agent. The waste metal of the cylinder head is thereby eliminated and the cooling characteristic thereof is improved.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a fugitive model for casting that becomes a gaseous state and disappears due to the action of molten metal cast, and in particular, 2 concerning a divided structure of a fugitive casting model used for casting engine cylinder heads.

[Conventional technology]

Traditionally, coreless (coreless) castings are produced by making an actual model using a material that becomes gaseous and disappearing due to the action of molten metal, and then pouring molten metal into this model while it is buried in sand.
Core Less) casting method is known (Special Publication Act 5
2-14206).

Furthermore, the structure of a diesel engine cylinder head manufactured by this casting method is also known.

FIG. 10 shows a partial cross section of a cylinder head of a diesel engine manufactured by the coreless VF manufacturing method. In the figure, 1 indicates the cylinder head, and 2
indicates the intake port. A valve seat surface 3 is formed on the lower surface of the cylinder head 1, and a valve stem hole 4 is provided above the valve seat surface 3, into which a valve stem of an intake valve (as shown) is inserted. In addition, in the figure, 5.6 indicates a water jacket.

This cylinder head 1 is made of a vanishing model (
Normally, foamed polystyrene is used as a fugitive model (hereinafter referred to as a poly model) for casting, but if you try to make a cylinder head using a poly model,
Due to the complicated shape of the cylinder head, it is extremely difficult to make a polygon model in one piece due to the process of casting the polyurethane model, so it is necessary to make the polygon model in parts. Therefore, in the cylinder head shown in Fig. 10, the parting vA
(Parting lines) A, B, and C are set, and the poly model for casting this cylinder head 1 is horizontally divided into four parts by the parting lines.

The parting line A is located directly above the valve seat surface 3 and is perpendicular to the intake port 2. Parting line B is intake port 2
, the pulp stem hole 4, and the water jacket 5, and the parting line C is the intake port 2,
It is set at a position crossing above the water jacket 6 and the pulp stem hole 4.

In this way, diesel engines do not require spark plugs and the combustion chamber is formed on the piston side, so
The lower surface of the cylinder head can be made into a horizontal surface, making it easy to divide the poly model in the horizontal direction.

The polygon models, which have been divided into multiple pieces, are then glued together using adhesive, but if the glue drips from the bonding surface, the dripping adhesive will disappear when poured and be replaced by molten metal, causing the adhesive to drip from the bonding surface. , causing the adhesion of waste meat. Therefore, it is desirable to make the parting lines A, B, and C horizontal as shown in FIG. 10, since this prevents the adhesive from dripping and improves productivity.

[Problem that the invention seeks to solve]

However, the cylinder head of a gasoline engine,
If an attempt is made to completely horizontally divide the image as described above, it will actually be disadvantageous in terms of performance. That is, in a gasoline engine, the cylinder head structure becomes complicated due to the addition of spark plugs, etc., and if the cylinder head is horizontally divided, there is a problem that there is waste, leading to an increase in weight, and deterioration of cooling performance.

In addition, the divided polygon models are bonded together using adhesive, but if the bonded surfaces shift, the cross-sectional area of the bonded surfaces that are actually cast will become smaller, increasing the stress per unit area, and reducing reliability. Danger arises. In particular, the valve train is a part of the cylinder head that is subject to considerable stress, and since the wall thickness is reduced as much as possible, if the mating surfaces shift, the strength will drop significantly. Therefore, accurate positioning of the polygon model is performed using the cylinder head bolt holes that fix the cylinder head to the cylinder block.

However, the bosses that form the cylinder head bolts usually do not reach the top of the cylinder head, except in HV engines, making it difficult to accurately position the cam journal section, lifter guide section, etc. at the top of the cylinder head. There is also the issue of becoming.

The present invention takes advantage of the large degree of design freedom of the coreless casting method and eliminates as much waste as possible, especially in the spark plug mounting area, for gasoline engines.

The purpose is to reduce the weight of the cylinder head and further improve cooling performance.

Furthermore, in addition to the above-mentioned object, the present invention also aims to provide a structure that allows accurate positioning of divided models.

[Means for solving problems]

A fugitive model for casting a cylinder head for an internal combustion engine according to the present invention, which meets this purpose, is used to cast a cylinder head for an internal combustion engine. A fugitive model for casting a cylinder head for a vehicle, the spark plug mounting portion of the cylinder head of the fugitive model and the combustion chamber wall forming the bottom surface of the water jacket are integrally connected, and the fugitive model is It is divided by a parting line that passes through the connection between the spark plug mounting portion and the combustion chamber wall and above the intake port and exhaust port adjacent to the water jacket.

Further, it is desirable to form a fitting part for positioning when the fugitive models are joined together on the dividing surface of the fugitive models.

[Effect]

In the fugitive model for casting a cylinder head for an internal combustion engine configured in this way, the fugitive model is divided by parting lines, so the degree of freedom in designing the cylinder head is increased and the shape of the cylinder head can be complicated. However, the model can be easily cast out.

That is, since there is a large degree of freedom in design, reinforcing portions of any shape can be formed anywhere, and the rigidity of the cylinder head can be increased. Therefore, the required strength of the cylinder head can be ensured even if the spark plug mounting portion is integrally connected to the combustion chamber wall forming the bottom surface of the water jacket and the thickness of the spark plug mounting portion is made thin.

In addition, since the spark plug mounting part is separated from the part where it connects to the combustion chamber wall, the thin part of the spark plug mounting part is not separated, and the wall thickness of the thin part will not become extremely thin due to misalignment of the model. , strength reduction is prevented.

Therefore, it is possible to largely eliminate waste material in the spark plug mounting portion, and the cooling capacity of the cylinder head is improved by cooling the waste material.

C Embodiment] Hereinafter, a preferred embodiment of the fugitive casting model for casting a cylinder head for an internal combustion engine according to the present invention will be described with reference to the drawings.

In this embodiment, the shape and division structure of the fugitive model will be explained using a completed cylinder head, and the actual fugitive model used to cast the cylinder head is not shown. Furthermore, expanded polystyrene is used as the fugitive model material.

First Embodiment Figures 1 to 4 show a cylinder head cast using a fugitive model (hereinafter referred to as a poly model) of a cylinder head for an internal combustion engine according to a first embodiment of the present invention. , specifically shows the cylinder head of a six-cylinder DOHC gasoline engine that has been cast and then machined.

FIG. 4 shows the entire cylinder head.

In the figure, 11 indicates a cylinder head, and 12 indicates a spark plug mounting portion of each cylinder. An intake-side valve lifter guide 13 is provided on the upper side of the figure with the spark plug mounting portion 12 at its center, and an exhaust-side valve lifter guide 14 is provided on the lower side. Further, cam journal parts 15a and 1 are provided on the left and right sides of each spark plug mounting part 12.
5b are provided respectively.

FIG. 1 shows a cross section of the cylinder head taken along line I-1 in FIG. 4. In the figure, 17 indicates the lower surface of the cylinder head, and a combustion chamber wall 43 forming a part of the combustion chamber 18 is formed on the lower surface 17 side of the cylinder head. Immediately above the combustion chamber wall 43, a spark plug mounting portion 12 is formed into which the above-mentioned spark plug (path shown) is inserted. The spark plug mounting portion 12 extends from the combustion chamber 18 toward the upper surface 41 of the cylinder head 11.
The lower end of the cylinder head is integrally connected to the combustion chamber wall 43 on the side of the lower surface 17 of the cylinder head. The lower part of the spark plug mounting part 12 is a thin-walled cylindrical part 12b, and a plug screw part 12a into which a spark plug (path shown) is screwed is formed at the lower end of the cylindrical part 12b.

A water jacket ILe is formed around the outer periphery of the spark plug mounting portion 12. The water jacket 19e includes the spark plug mounting portion 12 and the cylinder head members 44a and 44 that form the intake port 21 and the exhaust port 22.
b, and a combustion chamber wall 43 forming part of the combustion chamber 18. Thereby, the combustion chamber wall 43 in particular can come into contact with the walk jacket 19e over a wide area.

In addition, ribs 42a and 4 extending from the intake port 21 side to the exhaust port 22 side are provided in the thin wall portion of the spark plug mounting portion 12.
2b is provided. The ribs 42a, 42b are triangular in shape and become wider toward the top.

Water jackets x9f and 19g each having a parallelogram cross-sectional shape are provided at substantially midpoint in the vertical direction of the spark plug mounting portion 12 and around the outer periphery of the spark plug mounting portion 12. Cam journal parts 15a and 15b are provided above the water jackets 19f and 19g. In addition, in the figure, 26 indicates a blow-by gas passage, and 45
is an insertion hole into which a fuel injection valve (path shown) is inserted.

The cylinder throat 11 integrally constructed in this way is cast using a poly mold made with the same dimensions as the cylinder head 11. The poly model has a split structure due to the casting process, and the split positions of the poly model are set by parting lines, which will be described later. In this example, the poly model has parting lines.

It is divided into 6 parts by E, F, G, and H. That is,
Poly model is block 101.102.103.104
It is divided into 105 and 106.

In the cross-section of the cylinder head in FIG. 1, the cutout *D indicates the water jacket 19 which passes from the intake side side surface 22 of the cylinder 11 to the vicinity of the bottom of the blow-by gas passage 26.
It extends horizontally to the bottom surface of e. Then, the parting line 1 extends along the combustion chamber wall 43, which is the earthen wall of the fuel chamber 18 and the bottom surface of the water jacket 19e, and extends along the connection part between the spark plug mounting part 12 and the combustion chamber wall 43, i.e. It extends horizontally from the point where it traverses the plug threaded portion 12a and finishes descending the combustion chamber wall 43 toward the exhaust side side surface 23 of the cylinder head 11.

The parting line E extends from the intake side side surface 22 of the cylinder head 11 along the center line of the intake port 20, and extends so as to reach the bottom surface of the walk jacket l-19e. Further, a parting line E on the exhaust port 21 side also extends from the bottom surface of the water jacket 19e along the center line of the exhaust port 21, and extends toward the cylinder and toward the exhaust side side surface 23 of the throat 11.

Parting 6% F is above the intake port 20 and from the intake side side surface 22 of the cylinder head 11 to the plug tube 12.
It extends horizontally towards. Further, the parting line F is located above the exhaust port 21, and this portion is horizontal.

Parting line G is located above the above-mentioned parting line F, extends horizontally from the intake side side surface 22 of the throat 11 to the cylinder, crosses the water jacket 19r, the spark plug mounting part 12, and the water jacket 19g, and connects the cylinder head. It extends toward the exhaust side side surface 23 of 11.

The parting line H is located directly below the cam journal portions 15a, 15b, and extends horizontally from the intake side side surface 22 toward the exhaust side side surface 23 of the cylinder head 11.

FIG. 2 shows a cross section taken along line nn in FIG. 4.

In the figure, 17 indicates the lower surface of the throat of the cylinder.

A mountain-shaped combustion chamber is formed on the lower surface 17 side of the cylinder head, and water jackets L9a and 19b are provided diagonally above the combustion chamber 18. Above the water jackets 19a and 19b, an intake port 20 and an exhaust port 21 are provided on the left and right sides of the axis 10. One of the intake ports 20 is opened to the combustion chamber 18, and the other is opened to the intake side side surface 22 of the throat 11 to the cylinder. One of the exhaust ports 21 is connected to the combustion chamber 18
The other side is opened at the exhaust-side side surface 23 of the cylinder head 11. A water jacket 19c is located directly above the exhaust port 21.

Valve stem holes 24 and 25 are provided above the combustion chamber 18, into which valve stems of intake and exhaust valves (paths shown) are inserted. Below the valve stem hole 24 is the intake port 2
0, and the lower part of the valve stem hole 25 is opened to the exhaust port 21. Above the valve stem hole 24.25, the above-mentioned valve lifter guide 13.14 is provided. The upper part of the valve stem hole 24 opens toward the center of the valve lifter guide 13 , and the upper part of the valve stem hole 25 opens toward the center of the valve lifter guide 14 . Spring 424a, 25a that supports a valve coil spring (path shown) is provided on the upper end surface side of the valve stem hole 24.25.

Between the valve stem hole 24 and the valve stem hole 25,
A water jacket 19d extending toward the combustion chamber 18 is provided. Valve lifter guide 13. Cam journal parts 15a and 15b that support a camshaft (path shown) are provided diagonally above L4.

The above-mentioned cam journal parts 15a, 15b, valve lifter guide 13.14, and valve stem hole 24°2
5 are arranged in a straight line. In addition, in the figure, 2
6 indicates a blow-by gas passage, and the blow-by gas passage 26 is connected to the intake port 20 and to the cylinder rad 11.
It is provided on the exhaust side side surface 23 side of the.

In FIG. 2, the parting line extends from the intake side side surface 22 of the cylinder head 11 along the bottom surface of the blow-by gas passage 26, and extends in the horizontal direction to the bottom surface of the water jacket 19a. Then, the parting line extends from the upper part of the combustion chamber 18 along the mountain shape of the combustion chamber 18, and from the position below the mountain shape of the combustion chamber 18 to the water jacket 19.
The exhaust side side surface 23 of the cylinder head 11 passes through the bottom surface of b.
It extends horizontally.

The parting line E extends from the intake side side surface 22 of the cylinder Rad 11 along the center line of the intake port 20, and one end thereof is
It is orthogonal to the closeout vAD. The parting point vAE extends from the exhaust port 21 position that extends along the parting line at the upper part of the combustion chamber 18 and opens into the combustion chamber 18.
It extends along the center line of the cylinder head 11 and reaches the exhaust side side surface 23 of the cylinder head 11 .

The parting line F is above the intake port 20 and descends from the intake side side surface 22 of the cylinder head 11 along the curvature of the intake port 20, and is below the spring a24a and approximately midway in the vertical direction of the valve stem hole 24. It is moving horizontally. Then, it extends directly across the valve stem hole 24, the vicinity of the top surface of the water jacket 19, the valve stem hole 25, and the water jacket 19C to the exhaust side side surface 23 of the cylinder head 11.

A parting line G extends horizontally from a portion of the intake side side surface 22 of the cylinder head 11 located between the valve stem hole 24 and the valve lifter guide 13 to the valve stem hole 24.
．． 25 and extends toward the exhaust side surface 23 of the cylinder 11.

The parting line H is the intake side side surface 22 of the cylinder 7 door 11, and the valve lifter guide 13 and the cam journal 15a.
The valve lifter guide 13, 14 extends horizontally from a portion located between the valve lifter guide 13 and the valve lifter guide 13, 14 toward the exhaust side surface 23 of the cylinder toward the cylinder.

FIG. 3 shows a cross section taken along line mm in FIG. 4.

In the figure, numeral 31 indicates a current plate that controls the flow direction of cooling water within the water jacket. The current plate 31 has a rhombic shape that is elongated in the flow direction, and a recess 31a is formed in the current plate 31. This reduces weight and improves cooling effectiveness.

On the upstream and downstream sides of the current plate 31, there are ribs 32, 33, 34° 35 that control the flow direction of the cooling water in the same way as described above.
is provided. Moreover, a tight plug boss 36 which is a sand removal hole is provided above the current plate 31, and this tight plug boss 36 is provided with ribs 37 and 38 along the flow direction of the cooling water.

In the cross section of the cylinder head 11 shown in FIG. 3, the parting lines E, F, G, and H are set as follows. First, the lowermost parting line is the intake side side surface 22 of the cylinder head 11 and extends horizontally from below the intake manifold mounting screw hole 39 toward the exhaust side side surface 23 of the cylinder head 11.

The parting point vAE is the intake side side surface 22 of the cylinder head 11.
It extends diagonally downward from above the intake manifold mounting hole 39 and reaches between the ribs 32 and 33. The parting line E further extends diagonally downward from this position, passes between the ribs 34 and 35, and extends almost horizontally in the direction of the exhaust-side side surface 23 of the cylinder head 11.

The parting line F is the intake side side surface 22 of the cylinder Rad 11 and extends from directly above the parting line E mentioned above to the tight plug boss 36.
It extends horizontally toward the exhaust side surface 23 of the cylinder head 11 as it is. And parting line G
, H are set at the same level as in FIG. 1 and extend completely horizontally.

In this embodiment, five parting lines are set on the cylinder head 11, and the corresponding poly IJ model is divided into six parts, but the poly model is not limited to six parts, and the poly model can be further divided into many parts. For example, the degree of freedom in design increases [9ff
, it becomes possible to obtain an excellent cylinder head structure. Further, the present invention is applicable not only to gasoline engines but also to diesel engines.

Next, the operation in the first embodiment will be explained.

As described above, the cylinder head 11 has a parting vAD extending from the intake side side surface 22 of the cylinder head 11 toward the exhaust side side surface 23 of the cylinder head 11 .

E, F, G, and H are set, and the poly model used for casting the cylinder head 11 is divided into six parts by these parting lines. The poly model divided into six parts is accurately aligned, and the joining surfaces (partition vA) of the poly model are adhered and tightly attached with an adhesive.

In FIG. 1, the spark plug mounting portion 12 is formed across blocks 104, 105, and 106 of the cylinder head 11, and the lower thin-walled cylindrical portion of the spark plug mounting portion 12 is located at the protrusion 104. There is.

The lower end of the spark plug mounting portion 12 is integrally connected to the fuel chamber wall 43 forming the bottom surface of the water jacket, and the joint surface between the block 101 and the block 104 is the connection between the spark plug mounting portion 12 and the combustion chamber wall. The dividing plane of the connecting portion with 43 is set by a parting line extending along the bottom surface of the water jacket 19e.

Although the lower cylindrical portion 12b of the spark plug mounting portion 12 is joined to the block 101, it is not formed in the adjacent blocks 102 and 103, but is formed in the block 104. This is to prevent the wall thickness of the cylindrical portion 12b from becoming extremely thin due to positional deviation during adhesion due to division. In other words, this spark plug mounting part 1
By not dividing the cylindrical portion 12b of No. 2, the thickness of the spark plug mounting portion can be made thinner, and even if positional deviation occurs during adhesion, a uniform wall thickness can be obtained, and the required strength of the spark plug mounting portion 12 can be reduced. It is secured.

Furthermore, since lips 42a and 42b are provided on the outer periphery of the cylindrical portion of the spark plug mounting portion 12, the lips 42a and 42b are
2b serves as a reinforcing member, and the strength of the spark plug mounting portion 12 is increased. Therefore, the waste material of the spark plug mounting portion 12 can be significantly removed compared to a conventional cylinder head, and the weight of the cylinder head 11 is reduced. And, as the weight is reduced, the cooling performance of the cylinder head is improved.

Further, since the flow direction of the cooling water flowing through the water jacket 198 is controlled by the lips 42a and 42b, stagnation due to the joining of the cooling water is suppressed to a small level, and the cooling capacity is further enhanced.

Second Embodiment FIGS. 5 to 7 show a fugitive model for casting a cylinder head for an internal combustion engine according to a second embodiment of the present invention. The difference between the second embodiment and the first embodiment is the structure of the dividing plane of the evanescent model, and other parts are similar to the first embodiment, so similar parts are given the same reference numerals as in the first embodiment. The explanation of the parts that are the same will be omitted, and only the different parts will be explained.

In FIG. 5, a fitting portion 91 for alignment during joining is provided on the joint surface (parting line G) where the blocks 104 and 105 are joined.

The fitting portion 91 is located on the outer periphery of the spark plug mounting portion 12, and the fitting portion 91 has a convex shape on the block 104 side and a concave shape on the block 105 side.

Furthermore, a fitting portion 92 for alignment during joining is also provided on the joining surface (parting line H) where the blocks 105 and 106 are joined. The fitting portions 92 are formed directly below the cam journal portions 15a and 15b, and are convex on the block 105 side and concave on the block 106 side.

In FIG. 6, a fitting portion 93 is provided on the joining surface (parting line G) where the blocks 104 and 105 are joined together for positioning during joining.

The fitting portion 93 is located on the outer periphery of the spark plug mounting portion 12, and is fitted as shown in FIG. 5.

That is, the block 104 side is formed in a concave shape,
The block 105 side is formed in a convex shape.

Furthermore, fitting portions 94 and 95 are provided on the joint surface (parting line E) passing through the centers of the intake port 20 and the exhaust port 21 for positioning during joining. The fitting portion 94 is provided on a thick wall portion forming the intake port 21, and is formed in a convex shape on the block 102 side and concave on the block 103 side. Further, a fitting portion 96 is also provided on the joint surface between the block 101 and the block 104. That is, the tip of the spark plug mounting portion 21 is fitted into the combustion chamber wall 43.

In FIG. 7, fitting portions 97 and 98 are provided on the joining surface (second parting line F) where the blocks 103 and 104 are joined together for positioning during joining. The fitting portion 97 is located on the inner peripheral surface of the valve stem hole 24, and is formed in a concave shape on the block 103 side and convex on the block 104 side.

The fitting block 98 is located on the inner peripheral surface of the valve stem hole 25, and as described above, the block 103 side is formed in a concave shape, and the block 104 side is formed in a convex shape. Note that these fitting portions are not band-shaped but are scattered at various locations.

In the fugitive model constructed in this manner, each joining surface is provided with a concavo-convex fitting portion, so that the models can be aligned very quickly and accurately during adhesion. Therefore, reduction in area of the mating surfaces due to displacement of the mating surfaces is prevented, and the wall thickness is maintained at a predetermined thickness. Note that the alignment of blocks 101.102.1.03°104 is based on the third
The cylinder head bolt holes 81, 82 shown in the figures may also be utilized.

FIGS. 8 and 9 show a modification of the second embodiment.

In this embodiment, all fitting portions for alignment are provided on the outer wall side of the cylinder head, unlike the above-mentioned embodiments.

In FIGS. 8 and 9, a fitting portion 111 is provided at the joint surface between block 106 and block 105. The position of the block 106 in the left-right direction is restricted by stepped portions formed near both side walls of the block 105. Similarly, block 105 and block 104
A fitting part 112 is provided on the joint surface with the block 1.
A fitting portion 113 is also provided on the joint surface between 04 and 103. Furthermore, block 103 and block 102
A fitting part 114 is provided on the joint surface with the block 1.
02 and the block 101.
5 is provided. These fitting portions are formed in a band shape along the side wall of the cylinder head.

With the vanishing model constructed in this manner, accurate positioning of the model can be performed as in the second embodiment, so that no deviation occurs in the mating surfaces.

〔Effect of the invention〕

As explained above, when using the fugitive model for casting a cylinder head for an internal combustion engine of the present invention, the spark plug mounting part of the fugitive model and the combustion chamber wall forming the bottom surface of the water jacket are integrally connected, Since the fugitive model is divided by a parting line that passes through the connection between the spark plug mounting part and the combustion chamber wall and above the intake port and exhaust port adjacent to the water jacket, there is no reduction in strength. It becomes possible to reduce the thickness of the spark plug mounting portion, and it is possible to significantly eliminate unnecessary wall thickness of the spark plug mounting portion.

As a result, the weight of the cylinder head can be reduced, and the cooling capacity of the cylinder head can be improved by the amount of waste material removed. Therefore, the cooling performance around the combustion chamber wall and valve seat is improved.
, it becomes possible to increase the compression ratio and increase the output of the engine.

Moreover, if a fitting portion for positioning when the fugitive models are joined is formed on the dividing surface of the fugitive models, accurate and quick positioning can be performed. Therefore, it is possible to prevent a decrease in the strength of the cylinder due to displacement of the joint surfaces.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a cylinder head manufactured by a fugitive model for casting a cylinder head for an internal combustion engine according to a first embodiment of the present invention, and is a cross-sectional view taken along line 1-1 in FIG. 4; is a sectional view taken along the line H-It in Fig. 4, Fig. 3 is a sectional view taken along the III-III gland in Fig. 4, Fig. 4 is an overall plan view of the cylinder head shown in Fig. 1, and Fig. 5. is a cross-sectional view of a cylinder head manufactured by a fugitive model for casting a cylinder head for an internal combustion engine according to a second embodiment of the present invention; FIG. 6 is a cross-sectional view of the cylinder head shown in FIG. 5 viewed from a different direction; Fig. 7 is a sectional view of the cylinder throat shown in Fig. 5 viewed from another direction, Fig. 8 is a sectional view showing a modification of the second embodiment, and Fig. 9 is a sectional view of the cylinder head shown in Fig. 8. 10 is a sectional view of a conventional diesel engine cylinder head manufactured using a fugitive model. 11・・・・・・・・・・・・・・・・・・Cylinder head 12・・・・・・・・・・・・・・・・・・Spark plug mounting part 198・・・・・・・・・・・・・・・Water jacket 20・・・・・・・・・・・・・・・
・・Intake port 21・・・・・・・・・・・・・・・・
・・Exhaust port 43・・・・・・・・・・・・・・・・
... Combustion chamber wall, F ...... Parting line 101, 102.103.104.105.106...
...Block of cylinder head in DOHC engine divided by parting line Patent Applicant Toyota Motor Corporation Figure 3 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 11-5

Claims (2)

[Claims] (1) In a fugitive model for casting a cylinder head for an internal combustion engine, which is used to cast a cylinder head for an internal combustion engine and disappears by becoming a gaseous state due to the action of the molten metal being cast, ignition of the fugitive model The plug mounting portion and the combustion chamber wall forming the bottom surface of the water jacket are integrally connected, and the fugitive model is connected to the intake air adjacent to the water jacket through the connection portion between the spark plug mounting portion and the combustion chamber wall. A fugitive model for casting a cylinder head for an internal combustion engine, characterized in that it is divided by a parting line passing above a port and an exhaust port. (2) The fugitive model for casting a cylinder head for an internal combustion engine according to claim 1, wherein a fitting part for positioning when the fugitive models are joined is formed on a divided surface of the fugitive model.