JPH0780033B2 - Disappearance model for casting cylinder heads for internal combustion engines. - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an extinguishing model for casting, which disappears in a gas state by the action of cast molten metal, and particularly casts a cylinder head for an internal combustion engine. The present invention relates to a divided structure of a vanishing model for casting used in the.

[Conventional technology]

Conventionally, a coreless casting method in which a physical model is made of a material that turns into a gas state by the action of molten metal, and the molten metal is poured into the model while it is buried in sand to produce a casting. Is known (Japanese Patent Publication Sho 52-14206
Issue).

The structure of a cylinder head of a diesel engine 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 casting method.
In the figure, 1 indicates a cylinder head, and 2 indicates an intake port. On the lower surface of the cylinder head 1,
A valve seat surface 3 is formed, and a valve stem hole 4 into which a valve stem of an intake valve (not shown) is inserted is provided above the valve seat surface 3. In the figure, 5 and 6 represent water jackets.

As described above, the cylinder head 1 is cast using a vanishing model (usually referred to as a poly model because foam polystyrene is used as the vanishing contact model). In this case, since the cylinder head has a complicated shape, it is very difficult to integrally form the poly model due to the casting of the poly model, and it is necessary to divide the poly model into pieces. Therefore, in the cylinder head shown in FIG. 10, parting lines (dividing lines) A, B and C are set, and the poly model for casting the cylinder head 1 is divided into four parts in the horizontal direction by the parting line. Has been done. The parting line A is located immediately above the valve seat surface 3 and is orthogonal to the intake port 2.
The parting line B is set at a position crossing the intake port 2, the valve stem hole 4, and the water jacket 5, and the parting line C is a position crossing above the intake port 2, the water jacket 6, and the valve stem hole 4. Is set to.

In this way, the diesel engine does not require a spark plug and the combustion chamber is formed on the piston side,
The lower surface of the cylinder head can be a horizontal surface, which facilitates horizontal division of the poly model.

The poly model divided into a plurality of pieces is pasted with an adhesive, but when the adhesive drips from the pasting surface, the adhesive dripping during pouring disappears due to the molten metal and replaces it with molten metal. Causes adhesion of meat. Therefore, making the parting lines A, B, C horizontal as shown in FIG. 10 can prevent the adhesive from dripping, which is also desirable from the viewpoint of productivity.

[Problems to be solved by the invention]

However, if the cylinder head of a gasoline engine is to be divided horizontally, it will be disadvantageous in terms of performance. That is, in a gasoline engine, since the spark plug and the like are attached, the cylinder head structure becomes complicated, and if the horizontal division is attempted, there is a problem that the weight is increased and the cooling property is deteriorated.

Also, the divided poly models are bonded by an adhesive, but if the bonded surfaces shift, the cross-sectional area of the actually cast mating surface becomes smaller, the stress per unit area increases, and in terms of reliability. Danger occurs. In particular, the valve train is a heavy load on the cylinder head, but since the wall thickness is cut as much as possible, if the mating surfaces are misaligned, the strength is significantly reduced. Therefore, the poly model is accurately positioned by using the cylinder head bolt holes for fixing the cylinder head to the cylinder block.

However, the boss that forms the cylinder head bolt hole usually does not extend to the uppermost part of the cylinder head, apart from the OHV engine, which makes it difficult to accurately position the upper part of the cylinder head such as the cam journal part and the lifter guide part. There is also a problem.

INDUSTRIAL APPLICABILITY The present invention takes advantage of the large degree of freedom in designing the coreless casting method, and in particular reduces the weight of the cylinder head in a gasoline engine by eliminating the extraneous parts of the spark plug attachment part as much as possible, and further improves the cooling performance. The purpose is to

Further, in addition to the above-mentioned object, the present invention also aims to provide a structure capable of accurately aligning the divided models.

[Means for solving problems]

The extinguishing model for casting of a cylinder head for an internal combustion engine of the present invention which achieves this object is used for casting a cylinder head of an internal combustion engine, and an internal combustion engine which disappears in a gas state by the action of the molten metal to be cast. An extinguishing model for casting a cylinder head for an engine, wherein a thin-walled cylindrical portion extending to a combustion chamber wall forming a bottom surface of a water jacket is formed at a spark plug mounting portion of the cylinder head of the extinguishing model. Of the spark plug mounting portion and the combustion chamber wall are divided by a parting line extending along the bottom surface of the water jacket.

Further, it is desirable to form a fitting portion for alignment at the time of joining the disappearing models on the divided surface of the disappearing model.

[Action]

In the vanishing model for casting a cylinder head for an internal combustion engine configured in this way, the vanishing model is divided by the parting line, so that the degree of freedom in designing the cylinder head is increased and the shape of the cylinder head is complicated. However, casting of the model becomes easy. Since the degree of freedom in design is large, it is possible to form a freely-shaped reinforcing portion everywhere, and it is possible to enhance the rigidity of the cylinder head. Further, since the lower end of the thin cylindrical portion of the spark plug mounting portion can be supported by the combustion chamber wall forming the bottom surface of the water jacket, the strength required even if the thin cylindrical portion of the spark plug mounting portion is thinned. Is secured.

In addition, since the spark plug mounting portion and the combustion chamber wall are divided by the parting line extending along the bottom surface of the water jacket, they are not split at the middle part of the thin-walled cylindrical portion of the spark plug mounting portion, and are thin due to the displacement of the model. The wall thickness of the cylindrical portion does not become extremely thin, and the reduction in strength is prevented.

Therefore, it is possible to largely eliminate the mess of the spark plug attachment portion, and the cooling capacity of the cylinder head is improved because the scab is not required to be cooled.

〔Example〕

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

In the present embodiment, the shape and division structure of the fugitive model are described with the cylinder head in a completed state, and the actual fusible model used for casting the cylinder head is not shown. Further, expanded polystyrene is used as the disappearing model material.

First Embodiment FIGS. 1 to 4 show a cylinder head cast by using a vanishing 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. In particular, the cylinder head of a 6-cylinder DOHC gasoline engine machined after casting is shown.

FIG. 4 shows the entire cylinder head. 11 in the figure
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 right side of the engine with a straight line connecting a plurality of spark plug mounting portions 12 as a center in the left-right direction of the engine, and an exhaust side valve lifter guide 14 is provided on the left side. . Further, cam journal portions 15a and 15b are provided on the right and left of each spark plug attachment portion 12, respectively.

FIG. 1 shows a cross section of the cylinder head taken along the line II of FIG. In the figure, 17 indicates the lower surface of the cylinder head, and a combustion chamber wall 43 that defines a part of the combustion chamber 18 is formed on the cylinder head lower surface 17 side. Immediately above the combustion chamber wall 43, a spark plug attachment portion 12 into which the above-mentioned spark plug (not shown) is inserted is formed. The spark plug mounting part 12 is
It extends from the combustion chamber 18 toward the upper surface 41 of the cylinder head 11, and the lower end of the spark plug attachment portion 12 is integrally connected to the combustion chamber wall 43 on the cylinder head lower surface 17 side. A lower portion of the spark plug mounting portion 12 is a thin-walled cylindrical portion 12b, and a plug screw portion 12a into which an ignition plug (not shown) is screwed is formed on the lower portion of the thin-walled cylindrical portion 12b. Therefore, also in the poly model which will be described later, a thin cylindrical portion 12b extending to the combustion chamber wall 43 of the poly model is formed in the spark plug mounting portion 12 of the poly model.

On the outside of the spark plug mounting part 12, a water jacket 19
e is formed. The water jacket 19e is surrounded by the spark plug mounting portion 12, cylinder head members 44a and 44b forming the intake port 20 and the exhaust port 21, and a combustion chamber wall 43 forming a part of the combustion chamber 18. As a result, the combustion chamber wall 43 can contact the water jacket 19e with a large area.

In addition, in the thin portion of the spark plug mounting portion 12, the intake port
Ribs 42a and 42b extending in a direction connecting the 20 and the exhaust port 21 are provided. The ribs 42a and 42b have a triangular shape in which the width becomes wider as it goes upward.

Water jackets 19f and 19g each having a parallelogram cross section are provided at a substantially intermediate position in the vertical direction of the spark plug mounting portion 12b and outside the spark plug mounting portion 12. Above the water jackets 19f and 19g, the cam journal section 1
5a and 15b are provided. In the figure, 26 indicates a blow-by gas passage, and 45 is an insertion hole into which a fuel injection valve (not shown) is inserted.

The integrally formed cylinder head 11 is cast using a poly model having the same dimensions as the cylinder head 11. The poly model has a divided structure due to the casting condition, and the dividing position of the poly model is set by a parting line described below. In this embodiment, the poly model is divided into 6 by the parting lines D, E, F, G and H. That is, the poly model is divided into blocks 101, 102, 103, 104, 105, 106.

In the cross section of the cylinder head in FIG. 1, the parting line D
Extends horizontally from the intake side surface 22 of the cylinder head 11 through the vicinity of the bottom surface of the blow-by gas passage 26 to the bottom surface of the water jacket 19e. Then, the parting line D extends along the bottom surface of the water jacket 19e (which is also the upper surface of the combustion chamber wall 43) and crosses the plug screw portion 12a to finish descending the combustion chamber wall 43 from the cylinder head 11
It extends horizontally up to the exhaust side surface 23. Therefore, the lower end of the thin cylindrical portion 12b of the spark plug mounting portion of the poly model and the combustion chamber wall 43 of the poly model are divided by the parting line D extending along the bottom surface of the water jacket 19e.

The parting line E extends from the intake side surface 22 of the cylinder head 11 along the center line of the intake port 20 and
It has reached the bottom of 19e. The 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 to the exhaust side surface 23 of the cylinder head 11.

The parting line F extends above the intake port 20 and extends substantially horizontally from the intake side surface 22 of the cylinder head 11 toward the spark plug mounting portion 12. Furthermore, the parting line F extends downward along the outer periphery of the spark plug mounting portion and extends into the water jacket.
Up to 19e. The parting line F is the water jacket 19e.
From above to the outer periphery of the spark plug attachment portion, and from there, bends to the exhaust port side surface 23 and extends to the exhaust port side surface 23. The part of the parting line F located above the exhaust port 21 is substantially horizontal.

The parting line G is located above the parting line F and extends horizontally from the intake-side side surface 22 of the cylinder head 11 across the water jacket 19f, the spark plug mounting portion 12, and the water jacket 19g, and the exhaust-side side surface of the cylinder head 11. It extends to 23.

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

FIG. 2 shows a cross section taken along the line II-II in FIG.
In the drawing, 17 indicates the lower surface of the cylinder head. A mountain-shaped combustion chamber 18 is formed on the lower surface 17 side of the cylinder head, and a water jacket 19 is formed diagonally above the combustion chamber 18.
a and 19b are provided. Above the water jackets 19a, 19b, an intake port 20 and an exhaust port 21 are provided on the right and left with the cylinder head axis 10 as the center. One end of the intake port 20 is opened to the combustion chamber 18, and the other end is opened to the intake side surface 22 of the cylinder head 11. One end of the exhaust port 21 is opened to the combustion chamber 18, and the other end is opened to the exhaust side surface 23 of the cylinder head 11. A water jacket 19c is located directly above the exhaust port 21.

Above the combustion chamber 18, there are provided valve stem holes 24 and 25 through which the valve stems of intake and exhaust valves (not shown) are inserted. The lower end of the valve stem hole 24 is opened to the intake port 20, and the lower end of the valve stem hole 25 is opened to the exhaust port 21. Valve lifter guides 13 and 14 are provided above the valve stem holes 24 and 25. The upper end of the valve stem hole 24 opens toward the center of the valve lifter guide 13, and the upper end of the valve stem hole 25 opens toward the center of the valve lifter guide 14. Valve stem hole 2
Spring grooves 24a, 25a for supporting a valve coil spring (not shown) are provided on the upper end surface side of 4,25.

A water jacket 19d having a cross-sectional shape extending toward the combustion chamber 18 is provided between the valve stem hole 24 and the valve stem hole 25. Cam journal portions 15a and 15b that support a cam shaft (not shown) are provided obliquely above the valve lifter guides 13 and 14, respectively. Cam journals 15a and 15b, valve lifter guides 13 and 14, valve stem hole
24 and 25 are arranged in a straight line. In the figure, 26 indicates a blow-by gas passage.
The reference numeral 26 is provided below the intake port 20 and near the exhaust side surface 23 of the cylinder head 11.

In FIG. 2, the parting line D extends from the intake side surface 22 of the cylinder head 11 along the vicinity of the bottom surface of the blow-by gas passage 26, and extends horizontally to the bottom surface of the water jacket 19a. Then, the parting line D extends along the upper surface of the upper wall of the combustion chamber 18 along the chevron of the combustion chamber 18, and from the position below the chevron of the combustion chamber 18 through the bottom surface of the water jacket 19b to the exhaust of the cylinder head 11. It extends horizontally to the side surface 23.

The parting line E extends from the intake side surface 22 of the cylinder head 11 along the center line of the intake port 20, and one end thereof is orthogonal to the parting line D. The parting line E extends along the parting line D in the upper portion of the combustion chamber 18, extends from the position of the exhaust port 21 opening to the combustion chamber 18 along the center line of the exhaust port 21, and forms the exhaust side surface of the cylinder head 11. It has reached 23.

The parting line F descends above the intake port 20 and from the intake side surface 22 of the cylinder head 11 along the curvature of the intake port 20, below the spring groove 24a, and in the valve stem hole 24.
It moves horizontally in the middle of the vertical direction. And
As it is valve stem hole 24, near the top surface of water jacket 19d, valve stem hole 25, water jacket 19c
And extends to the exhaust side surface 23 of the cylinder head 11. The parting line G is the intake side surface 22 of the cylinder head 11.
And the valve stem holes 24, 25 in the horizontal direction from the portion located between the valve stem hole 24 and the valve lifter guide 13.
And extends in the direction of the exhaust side surface 23 of the cylinder head 11.

The parting line H is the intake-side side surface 22 of the cylinder head 11 and extends horizontally from the portion located between the valve lifter guide 13 and the cam journal 15a.
The upper end of the cylinder head is extended to the exhaust side surface 23 direction of the cylinder head 11.

FIG. 3 shows a cross section taken along the line III-III in FIG. In the figure, reference numeral 31 denotes a straightening vane that controls the flow direction of the cooling water in the water jacket. The current plate 31 has a rhombus shape elongated in the flow direction, and the recess 31 is formed in the current plate 31.
a is formed. Thereby, the weight reduction and the cooling effect are improved.

Ribs 32, 33, 34, 35 for controlling the flow direction of the cooling water are provided on the upstream side and the downstream side of the flow straightening plate 31 as described above. Further, a tight plug boss 36, which is a sand removing hole, is provided above the straightening vane 31.
Ribs 37, 38 are provided on the.

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

The parting line E extends obliquely downward from above the intake manifold side mounting screw hole 39 on the intake side surface 22 of the cylinder head 11 and reaches between the ribs 32 and 33. The parting line E extends further diagonally downward from this position and the rib 34
From the position where the passage between the rib 35 and the rib 35 is completed, it extends substantially horizontally to the exhaust side surface 23 of the cylinder head 11.

The parting line F extends substantially horizontally on the intake side surface 22 of the cylinder head 11 and directly above the parting line E toward the tight plug boss 36, and further on the exhaust side surface 23 of the cylinder head 11.
Has been extended to. The positions of the parting lines G and H are the first
It is set at the same level as the figure and extends completely horizontally.

In the present embodiment, five parting lines are set on the cylinder head 11 and the poly model 6 corresponding thereto is divided into six. However, the poly model 6 is not limited to six, and the poly model may be divided into a large number. If so, the degree of freedom in design is increased, and it becomes possible to obtain a functionally superior cylinder head structure. Further, the present invention is applicable not only to a gasoline engine but also to a diesel engine.

Next, the operation of the first embodiment will be described.

The cylinder head 11 has a side surface on the intake side of the cylinder head 11.
Parting lines D, E, G, H extending from 22 toward the exhaust side surface 23 of the cylinder head 11 are set, and the poly model used for casting the cylinder head 11 is 6 by these parting lines. It is divided. The 6-divided poly model is accurately aligned, and the joining surface (parting line) of the poly model is brought into close contact with each other and bonded with an adhesive.

In FIG. 1, the spark plug mounting portion 12 is formed over the blocks 104, 105, 106 of the cylinder head 11, and the thin-walled cylindrical portion of the spark plug mounting portion 12 is a block.
Located at 104. The lower end of the spark plug mounting portion 12 of the poly model is joined to the fuel chamber wall 43 forming the bottom surface of the water jacket of the poly model, and the joint surface between the block 101 and the block 104 is the spark plug mounting portion 12 and The dividing surface with the combustion chamber wall 43 is set by a parting line D extending along the bottom surface of the water jacket 19e.

The thin-walled cylindrical portion 12b below the spark plug mounting portion 12 is formed on the block 104 instead of being formed on the adjacent blocks 102 and 103 even though it is joined to the block 101.
This is because the cylindrical part 12
This is to prevent the wall thickness from becoming extremely thin. In other words, by not dividing the cylindrical portion 12b of the spark plug mounting portion 12, it is possible to reduce the thickness of the spark plug mounting portion, and even if a position shift occurs during bonding, a uniform wall thickness can be obtained and required. The strength of the spark plug mounting portion 12 is secured.

Further, a rib 42 is provided on the outer periphery of the cylindrical portion of the spark plug mounting portion 12.
Since the ribs 42a and 42b are provided, the ribs 42a and 42b serve as reinforcing members and the strength of the spark plug mounting portion 12 is enhanced. Therefore, the small portion of the spark plug attachment portion 12 can be largely removed as compared with the conventional cylinder head, and the weight of the cylinder head 11 is reduced. Then, the cooling performance of the cylinder head is improved by the amount of the reduced weight.

In addition, the cooling water flowing through the water jacket 19e is rib 42
Since the flow direction is controlled by a and 42b, the stagnation due to the confluence of the cooling water is suppressed and the cooling capacity is further enhanced.

Second Embodiment FIGS. 5 to 7 show an extinguishing model for casting of a cylinder head for an internal combustion engine according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in the structure of the division surface of the vanishing model, and the other parts are in conformity with the first embodiment. Therefore, the conforming parts are designated by the same reference numerals as those in the first embodiment. The description of the parts conforming to is omitted, and only the different parts will be described.

In FIG. 5, the joint surface (parting line G) where the blocks 104 and 105 are joined is provided with a fitting portion 91 for alignment during joining. The fitting portion 91 is located on the outer periphery of the spark plug mounting portion 12, and the fitting portion 91 is formed so that the block 104 side is concave and the block 105 side is convex.

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

In FIG. 6, a fitting surface 93 for joining the blocks 104 and 105 (parting line G) is provided with a fitting portion 93 for alignment during joining. The fitting portion 93 is located on the outer periphery of the spark plug mounting portion 12, and has the same fitting as the fitting shown in FIG. That is, block 10
The 4 side is formed in a concave shape, and the block 105 side is formed in a convex shape.

Fitting portions 94 and 95 are provided on a joining surface (parting line E) that passes through the centers of the intake port 20 and the exhaust port 21 for alignment during joining. The mating portion 94 is the intake port 21.
It is provided on the thick wall portion forming the, and the block 102 side is formed in a convex shape and the block 103 side is formed in a concave shape. Further, the 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 attachment portion 21 is fitted so as to project into the groove formed in the combustion chamber wall 43.

In FIG. 7, fitting portions 97 and 98 are provided on the joint surface (second parting line F) where the block 103 and the block 104 are joined, for alignment during joining. Mating part 97
Is located on the inner peripheral surface side of the valve stem hole 24, and the block 103 side is formed in a concave shape and the block 104 side is formed in a convex shape. The fitting portion 98 is located on the inner peripheral surface side of the valve stem hole 25, and the block 103 side is formed in a concave shape,
The block 104 side is formed in a convex shape. It should be noted that these fitting portions are not strip-shaped but are scattered at each place.

In the disappearing model constructed in this manner, since the joint portions are provided with the concave-convex fitting portions, the models can be aligned with each other very quickly and accurately during bonding. Therefore, the reduction of the area of the mating surface due to the deviation of the mating surface is prevented, and the wall thickness is secured to a predetermined thickness. In addition, block 10
The cylinder head bolt holes 81, 82 shown in FIG. 3 may be used for the alignment of the 1, 102, 103, 104.

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

In the present embodiment, all the fitting portions for alignment are provided on the outer wall side of the cylinder head, unlike the above-mentioned embodiments.
8 and 9, block 106 and block 1
A fitting portion 111 is provided on the joint surface with 05. The position of the block 106 in the left-right direction is regulated by a step portion formed near both side walls of the block 105. Similarly, a fitting portion 112 is provided on the joining surface between the blocks 105 and 104, and a fitting portion 113 is also provided on the joining surface between the blocks 104 and 103.
Is provided. In addition, blocks 103 and 102
The fitting portion 114 is provided on the joining surface between the and, and the fitting portion 115 is also provided on the joining surface between the block 102 and the block 101.
These fitting portions are formed in a band shape around the side wall of the cylinder head.

In the vanishing model constructed in this way, the model can be accurately positioned as in the second embodiment, so that no misalignment occurs in the mating surfaces.

〔The invention's effect〕

According to the extinguishing model for casting of the cylinder head for an internal combustion engine of the present invention, a thin-walled cylindrical portion extending to the combustion chamber wall forming the bottom surface of the water jacket is formed at the spark plug mounting portion of the extinguishing model, Since the thin-walled cylindrical portion of the spark plug mounting portion and the combustion chamber wall are divided by the parting line extending along the bottom surface of the water jacket, the spark plug mounting portion of the thin-walled cylindrical portion is secured while ensuring the strength of the thin-walled cylindrical portion. It is possible to sufficiently thin the thin-walled cylindrical portion, and it is possible to largely eliminate the uselessness of the spark plug mounting portion.

As a result, it is possible to reduce the weight of the cylinder head and to improve the cooling capacity of the cylinder head by the amount of the extraneous material removed. As a result, the cooling property around the wall of the combustion chamber and the valve seat is improved, the compression ratio of the engine can be increased, and the engine output can be increased.

Further, if a fitting portion for alignment when joining the disappearing models is formed on the dividing surface of the disappearing model, accurate and quick positioning can be performed. Therefore, there is an effect that it is possible to prevent the strength of the cylinder head from being lowered due to the displacement of the joint surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a cylinder head manufactured by a vanishing model for casting a cylinder head for an internal combustion engine according to a first embodiment of the present invention, which is a cross section taken along line II of FIG. Fig. 2, Fig. 2 is a sectional view taken along the line II-II in Fig. 4, Fig. 3 is a sectional view taken along the line III-III in Fig. 4, and Fig. 4 is an overall plan view of the cylinder head shown in Fig. 1. 5 and 5 are cross-sectional views of a cylinder head manufactured by a casting extinction model of a cylinder head for an internal combustion engine according to a second embodiment of the present invention, and FIG. 6 shows the cylinder head shown in FIG. FIG. 7 is a sectional view showing the cylinder head shown in FIG. 5 from another direction, FIG. 8 is a sectional view showing a modified example of the second embodiment, and FIG. 9 is shown in FIG. Fig. 10 is a sectional view of the cylinder head shown from another direction. It is a cross-sectional view of a diesel engine cylinder head. 11 …… Cylinder head 12 …… Ignition plug mounting part 19e …… Water jacket 20 …… Intake port 21 …… Exhaust port 43 …… Combustion chamber wall D, F …… Partition line 101,102,103,104,105,106 …… DOHC engine divided by parting line Block of cylinder head in

Claims (2)

[Claims] 1. A vanishing model for casting of a cylinder head for an internal combustion engine, which is used for casting a cylinder head of an internal combustion engine and disappears in a gas state by the action of a molten metal cast therein. A thin-walled cylindrical portion that extends to the combustion chamber wall forming the bottom surface of the water jacket is formed in the spark plug mounting portion of the spark plug, and the thin-walled cylindrical portion of the spark plug mounting portion and the combustion chamber wall of the fugitive model are connected to the water A vanishing model for casting a cylinder head for an internal combustion engine, characterized by being divided by a parting line extending along the bottom surface of the jacket. 2. The extinguishability for casting of a cylinder head for an internal combustion engine according to claim 1, wherein a fitting portion for aligning the extinguishing model when joining the extinguishing model is formed on a dividing surface of the extinguishing model. model.