JPS6329860Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a cylinder head in an internal combustion engine.

[Conventional technology and its issues]

In general, the cylinder head of an internal combustion engine is made of cast iron and has a complex structure with a fuel valve, intake/exhaust ports, water jacket, etc. The cylinder head is connected through a gasket packing. To fix it to the cylinder block,
A large number of cylinder head bolts are required, and they are provided at positions that do not interfere with each of the above-mentioned members.

On the other hand, internal combustion engines are currently becoming smaller and faster, especially engines with high turbocharging, and the pressure in the cylinder is becoming higher and higher, so the tightening force of cylinder head bolts is also increasing. As a result of their measurements, they found that the surface pressure was extremely low in the middle between each bolt of this large number of cylinder head bolts, and that this was the cause of gas leakage. Also,
When the tightening force of the cylinder head bolt is increased, the tightening force increases with uneven surface pressure distribution between the cylinder head and cylinder block, which increases deformation of the cylinder liner and reduces lubricating oil consumption. It has been discovered that this causes problems that accelerate ring wear.

However, in the conventional technology, only cylinder head bolts with increased strength are used to increase the tightening force, and ribs of a certain height are protruded between the columnar bosses for these bolts to create a connected structure. (For example, see Figures 1 and 2 of Japanese Utility Model Publication No. 49-36987).

To explain this in detail, Figure 1 is a horizontal cut at the middle of the height of the cylinder head, where 1 is the intake port, 2 is the exhaust port, 3 is the fuel injection nozzle insertion hole, and 4 ₁ to 4 ₆ are the cylinder head. Bolt hole 5 is
A rib of some height is shown projecting between columnar bosses 10, 10 having cylinder head bolt holes 4 in the water jacket 7 on the back side of the combustion surface 6 of the cylinder head. FIG. 2 shows a sectional view taken from A to A in FIG. 1, with reference numeral 8 indicating a cylinder head bolt, and 9 indicating a nut of the cylinder head bolt 8.

Therefore, when the cylinder head bolt 8 is tightened, the tightening force is transmitted directly below the columnar boss 10 having the cylinder head bolt hole 4, as shown by the arrow in FIG. 2, so that a uniform surface pressure is applied to the combustion surface 6. is not obtained. On the other hand, since the wall thickness on the side of the combustion surface 6 is made thinner for cooling and the bending rigidity is lowered, most of the tightening force of the cylinder head bolt 8 is applied only to the area around the bolt. Therefore, from these reasons, the surface pressure of the gasket packing around the cylinder head bolt 8 is high, but as it moves away from the cylinder head bolt 8, the surface pressure decreases extremely and becomes uneven as a whole. (See Figure 4, dash-dotted line).

In addition, in order to make the surface pressure distribution of the gasket packing uniform, it is possible to change the thickness of the gasket packing as appropriate, but manufacturing such a gasket packing is extremely complicated, which not only increases the cost but also increases the production time. Inconsistency over time may even cause trouble.

[Means to solve the problem]

Therefore, the present invention aims to prevent the occurrence of trouble by improving the conventional technology shown in Fig. 1 and using a simple gasket packing that is easy to manufacture. The gist is that a part of the wall facing the water jacket 7 of the cylinder head is constituted by columnar bosses 10, 10, respectively, each having a cylinder head bolt hole 4 through which the cylinder head bolt 8 is inserted. In the cylinder head of an internal combustion engine, a rib of approximately constant thickness is provided to connect the pair of bosses 10, 10 and protrude from the back surface of the combustion surface 6 in the cylinder head. 1
Bracket-like ribs 11 are formed diagonally downward from approximately the middle of the heights of 0 and 10 and cross each other, and the cylinder of the columnar boss 10 is located at a position where the bracket-like ribs 11 protrude into the water jacket 7. It is located in the cylinder head of an internal combustion engine in which the head bolt hole 4 is enlarged in diameter 13.

〔Example〕

The configuration of the present invention will be explained in detail with reference to the embodiment shown in FIG. FIG. 3 corresponds to the section A--A in FIG. 1, and the same parts as those in the prior art in FIGS. 1 and 2 are designated by the same reference numerals.

Now, in FIG. 3, in this embodiment, between the columnar bosses 10 having the cylinder head bolt holes 4, there is a position corresponding to the upper part of the bore grommet (not shown) of the gasket packing (the reference numeral 12 in FIG. 1 is a position corresponding to the bore). A bracket-shaped rib 11 is provided in the water jacket 7 to protrude from the water jacket 7.
This bracket-like rib 11 is connected to the columnar boss 10.
It is connected to the bracket-like ribs 11 of the adjacent columnar bosses 10 at an angle of about 45 degrees diagonally downward at approximately the midpoint in the height direction of the bosses 10 so as to intersect with each other.

In addition, the inner diameter of the columnar boss 10 having the cylinder head bolt hole 4 is enlarged 13 near the protruding combustion surface of the bracket-like rib 11 (slightly below the upper end of the rib 11). As shown, the main part of the transmission of bolt tightening force is supported by this bracket-like rib 11.

As a result, the surface pressure distribution between the cylinder head and the cylinder block in this example is as shown by the solid line in Fig. 4, which shows the test results of various cylinder heads. By lowering the surface pressure in the vicinity immediately below the columnar bosses 10, and instead increasing the surface pressure between the columnar bosses 10, 10, a uniform surface pressure was obtained as a whole. In addition, what is shown by the one-dot chain line in FIG. 4 is a surface pressure distribution diagram composed only of the ribs 5 of the prior art, and it is clear that this is insufficient.

Furthermore, in another embodiment of the present invention shown in FIG.
The tightening force of the cylinder head bolt 8 is stopped from being transmitted to the columnar boss 10 having the cylinder head bolt hole 4, and the columnar boss 10 merely has the function of forming the water jacket 7. It is transmitted to the combustion surface 6 through the bracket-shaped rib 11 provided on the side of the gasket, thereby making the surface pressure distribution of the gasket packing more uniform.

[Effect of idea]

According to the present invention, the following beneficial effects can be expected.

Since the bracket-like ribs are provided diagonally downward from approximately the middle of the height of the pair of columnar bosses and intersect with each other, the complicated cylinder head is given rigidity and the tightening force of the cylinder head bolt is reduced. In addition, the surface pressure between the cylinder head and the cylinder block can be uniformly distributed as shown in FIG. 4, and a simple gasket packing can be used. Therefore, it can be made suitable for internal combustion engines with high cylinder pressure.

Since the inner diameter of the columnar boss at the position where the bracket-shaped rib protrudes into the water jacket is enlarged and the wall thickness is made thinner, the tightening force transmitted from directly below the columnar boss to the combustion surface is reduced, and in return, the bracket The clamping force is transmitted to the shaped ribs, and together with the above, it is possible to achieve a more uniform surface pressure. Furthermore, since the wall thickness is reduced, cooling of the cylinder head can also be improved.

[Brief explanation of the drawing]

Figure 1 is a horizontal cross-sectional view of the conventional example, and Figure 2 is the 1st
3 shows a cross-sectional view corresponding to FIG. 1 A-A in the embodiment of the present invention, and FIG. 4 shows a surface pressure distribution diagram.
FIG. 5 shows another embodiment of the invention. 4... Cylinder head bolt hole, 6... Combustion surface, 7... Water jacket, 8... Cylinder head bolt, 10... Columnar boss, 11... Bracket-shaped rib, 13... Inner diameter.

Claims (1)

[Scope of Claim for Utility Model Registration] A columnar boss 10 having a cylinder head bolt hole 4 through which a cylinder head bolt 8 is inserted in a part of the wall facing the water jacket 7 of the cylinder head;
10, and from the back side of the combustion surface 6 in the water jacket 7, these pair of bosses 1
In the cylinder head of an internal combustion engine, the ribs are connected to each other and have a protruding rib having a substantially constant thickness.
Bracket-like ribs 11 are formed diagonally downward from approximately the middle of the height and intersect with each other, and the cylinder head bolt hole 4 of the columnar boss 10 is located at a position where the bracket-like ribs 11 protrude into the water jacket 7. Cylinder head of an internal combustion engine with enlarged diameter 13.