JPS6347633Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a cylinder head for an internal combustion engine.

The cylinder head is attached to the top surface of the cylinder block and forms a combustion chamber together with the piston and cylinder, and is generally made of several cylinders by integral casting.

By the way, in such a cylinder head, as shown in Fig. 1, the lower surface 1 of the head, which forms the ceiling of the combustion chamber, reaches the highest temperature during operation, so that due to thermal strain, the cylinder head is distorted in the longitudinal direction as shown by the dashed line in the figure. However, since the cylinder block 2 is tightened with bolts (not shown), excessive thermal stress is applied to the lower surface 1 of the head, causing cracks and damage, and the tightening force of the gasket 3 is partially weakened, resulting in combustion. There are problems such as gas leakage.

As a countermeasure against this problem, as shown in Fig. 2, a notch 4 is formed on the lower surface 1 of the cylinder head to partition the bores, and this notch 4 absorbs thermal strain and suppresses the generation of thermal stress. (Refer to "Principles of Automotive Engine Planning" by Osamu Hirao, published by Sankaido in 1972, p. 224).

However, in this case, the notch 4 is not formed over the entire width of the cylinder head, but is formed on the lower surface 1 of the head.
In addition, the formation of the notch 4 creates a thin wall part, and there is a risk that thermal stress will be concentrated in that part, causing cracks and damage.

This idea was devised by focusing on these problems.A groove is formed on the lower surface of the cylinder head facing the cylinder block to partition the bores over the entire width of the head, while a groove is formed on the inner surface facing the cooling water channel. The object of the present invention is to provide a cylinder head in which reinforcing ribs are correspondingly formed to avoid the generation of excessive thermal stress.

This invention will be explained below with reference to the embodiments shown in FIGS. 3 and 4. Note that the same parts as in FIGS. 1 and 2 are designated by the same reference numerals.

In FIG. 3, a groove 6 is formed in the lower surface 1 of the cylinder head, which partitions the combustion chamber wall portions 5, 5 corresponding to the cylinder bores, over the entire width of the cylinder head.

The groove 6 is formed so as to avoid the bolt hole 7 formed around the combustion chamber wall portion 5.

As shown in FIG. 4, reinforcing ribs 8 are provided protruding from the inner surface of the lower surface 1 of the cylinder head on the cooling water channel side in correspondence with the grooves 6 mentioned above.

According to such a structure, thermal strain generated on the lower surface 1 of the cylinder head during operation is absorbed by the groove 6, but in this case, since the groove 6 is formed over the entire width of the cylinder head, it is different from the conventional one. Therefore, even the thermal strain on both sides of the lower surface 1 of the cylinder head can be absorbed.

Therefore, the thermal stress on the lower surface 1 of the cylinder head is reduced, and the occurrence of cracks, breakage, and reduction in the tightening force of the gasket 3 can be prevented.

Furthermore, reinforcing ribs 8 are formed on the inner surface of the lower surface 1 of the cylinder head on the side of the cooling channel in correspondence with the grooves 6, and the wall thickness at the grooves 6 is sufficiently thick to prevent cracks and damage from occurring in this area. It can be prevented.

As explained above, according to this invention, a groove is formed on the lower surface of the cylinder head to partition the bores over the entire width of the head, while on the inner surface on the side of the cooling channel,
Since the reinforcing ribs are formed in correspondence with the grooves, excessive thermal stress is not generated on the lower surface of the cylinder head, and the durability of the cylinder head and gas sealing properties can be improved.

[Brief explanation of drawings]

Fig. 1 is a schematic side view showing the installed state of the cylinder head, Fig. 2 is a bottom view showing a conventional cylinder head, Fig. 3 is a partial bottom view of the cylinder head showing an embodiment of this invention, Fig. 4 is also a schematic cross-sectional view. 1...Bottom surface of cylinder head, 6...Groove, 8...
Reinforced ribs.

Claims (1)

[Scope of utility model registration request] In a cylinder head for an internal combustion engine that is integrally formed with parts for several cylinders, a groove is formed on the lower surface of the head body to partition the bores over the entire width of the head.
A cylinder head for an internal combustion engine, characterized in that reinforcing ribs are formed on the inner surface of the cylinder head on the side of the cooling water passage in correspondence with the grooves.