JP3139078B2 - Aluminum alloy cylinder head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy cylinder head having a cooling water jacket.

[0002]

2. Description of the Related Art The lower surface of a cylinder head is in a thermally severe environment, and in particular, a partition wall between an intake port and an exhaust port is
Since it is formed to be thinner than the other parts of the cylinder head, a high thermal stress is generated when it is locally heated, and a thermal crack is easily generated. For this reason, conventionally, a cooling water passage for flowing cooling water is formed in the partition wall, and the partition wall is cooled to protect it from heat damage.

As shown in FIGS. 8 to 10, a conventional cylinder head of this type is provided with valve stem insertion holes 3 and 4 formed around the intake port 1 and the exhaust port 2 or from the ports 1 and 2 to the upper surface of the cylinder head. A cooling water jacket 5 is formed around the cylinder head.
To the pre-combustion chamber (injection port) 8 and communicates with the cooling water jacket 5 in the vicinity thereof. An inlet 9 of the cooling water passage 6 is opened at the back surface of the cylinder head, and cooling water from a cooling water jacket of a cylinder block (not shown) is sent to the cooling water passage 6 through the inlet 9. I have.

[0004]

When the cooling water passage 6 is used without being subjected to a rust-preventive treatment, corrosion scale and rust are generated on the inner peripheral surface of the cooling water passage 6 to hinder heat conduction. As a result, effective cooling of the partition walls becomes impossible, which is a major obstacle to increasing the engine output. For this reason, conventionally, a corrosion-resistant metal film is formed on the inner peripheral surface of the cooling water passage 6 to prevent corrosion scale, rust, etc., and to maintain thermal conductivity (Japanese Utility Model Application Laid-Open No. 55-4328). Gazette).

However, when the cylinder head is made of aluminum (aluminum alloy) due to recent demands for small size and light weight, contact corrosion occurs between the aluminum and the corrosion-resistant metal film depending on the material of the corrosion-resistant metal film. However, there is a problem that the strength of the partition wall is impaired. As a countermeasure, as shown in FIGS. 8 to 10, a pipe 10 made of a potential-low metallic material is provided on the inner peripheral surface of the cooling water passage 6.
(Japanese Utility Model Laid-Open No. 57-31544) has been proposed in which a scale is inserted to displace the scale.

However, in this configuration, in order to maintain the function, it is necessary to replace the inserted pipe with a new one every time the pipe is worn out, and the outlet of the cooling water passage 6 relatively close to the combustion surface is required. As a result, it was not possible to prevent the generation of corrosion scale and rust on the casting surface No. 11 and there was a problem that the maintenance of thermal conductivity was insufficient.

In view of the above circumstances, the present invention has been devised in order to provide an aluminum alloy cylinder head which does not require replacement of parts and can maintain heat conductivity more widely.

[0008]

According to the present invention, there is provided a cooling water passage connected to a cooling water jacket through an inter-valve portion, and a pipe made of a material having higher corrosion resistance than aluminum alloy is formed in the cooling water passage. At the same time, a corrosion-resistant member made of the above material is provided at the outlet of the cooling water passage so as to appropriately cover the casting surface.

[0009]

With the above construction, the pipe prevents corrosion scale and rust from being generated in the cooling water passage, and the corrosion-resistant member prevents corrosion scale and rust from being generated at the outlet.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 show a first embodiment of an aluminum alloy cylinder head according to the present invention. This aluminum alloy (JIS AC2B) cylinder head
A cooling water passage 26 is formed extending through the valve portion 23 between the intake port 21 and the exhaust port 22 to the vicinity of the hot plug 24 and connected to the cooling water jacket 25. The cooling water passage 26 is made of aluminum alloy. Also, a pipe 27 made of stainless steel (JIS 304 or JIS 308), which is a material having excellent corrosion resistance, is fitted therein, and the tip 28 of the pipe 27 is cut off at an angle to form a corrosion resistant member. That is, the tip 28 is connected to the outlet 2 of the cooling water passage 26.
9, the side communicating with the cooling water jacket 25 is opened as a notch 30, and the casting surface portion on the combustion surface 31 side and the side opposite to the cooling water jacket 25 is covered. I have. In addition, the total length of the pipe 27 is such that the tip 28 is abutted against the casting surface.
At least the intake / exhaust port 2 of the cooling water passage 26
It is formed so as to extend beyond the center position 32 between 1 and 22.

As shown in FIG. 3, a rotation preventing projection 33 is formed on the surface of the pipe 27 for positioning during press-fitting and for preventing displacement after press-fitting. Further, as shown in FIG. 4, fins 34 may be provided on the inner wall of the pipe in order to improve the cooling efficiency.

In this embodiment, as shown in FIGS. 1 and 2, a recess 35 (shown by oblique lines in the figure) that is covered by the tip 28 of the pipe 27 at the outlet 29 is omitted. The thickness is increased to increase the thermal strength.

With this configuration, the cooling water passage 2
6, the cooling water passage 26 which is thermally severe
The corrosion resistance of the outlet portion 29 is improved, and the thermal conductivity can be maintained over a wide range. That is, appropriate cooling in the thin valve portion 23 is achieved. Also, since there is no consumption of the pipe, there is no need for replacement or the like.

Next, a second embodiment of the present invention will be described with reference to FIGS.

In this embodiment, a stainless steel pipe 41 is press-fitted into the cooling water passage 26 and an outlet 29
On the combustion surface 31 side of the casting skin surface 42, a thickness of 0.
A stainless plate 43 of about 3 to 1.0 mm is provided by casting. On the lower surface of the stainless steel plate 43, a triangular prism-shaped anchor portion 44 for preventing displacement is formed.

As shown in FIG. 7, a stainless steel plate 43 is fixed to a core 45 that forms a cooling water jacket 25 by a steel wire 46 or an adhesive during casting of a cylinder head, as shown in FIG. Just do it. The stainless plate 43 may have any shape as long as it corresponds to the outlet portion 29.

In the above embodiment, stainless steel is shown as a material having excellent corrosion resistance, but pure aluminum (JIS 10
00 system) may be used.

[0019]

In summary, according to the present invention, the following excellent effects are exhibited.

Since a pipe made of a material having better corrosion resistance than the aluminum alloy is inserted into the cooling water passage and a corrosion-resistant member for covering the casting surface is provided at the outlet of the cooling water passage, there is no need to replace parts. At the same time, the generation of corrosion scale and rust in the cooling water passage and the outlet thereof can be prevented, and the cooling function can be maintained.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a first embodiment of a cylinder head made of an aluminum alloy according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a perspective view of a main part of FIG. 1;

FIG. 4 is a perspective view showing another embodiment of FIG. 3;

FIG. 5 is a plan sectional view showing a second embodiment of the present invention.

FIG. 6 is a sectional view taken along line BB of FIG. 5;

FIG. 7 is a perspective view of a core for describing the manufacturing method of FIG. 6;

FIG. 8 is a bottom view showing a conventional aluminum alloy cylinder head.

FIG. 9 is a sectional view taken along line CC of FIG. 8;

FIG. 10 is a sectional view taken along line DD in FIG. 8;

[Explanation of symbols]

23 Inter-valve portion 25 Cooling water jacket 26 Cooling water passage 27 Stainless steel pipe (Pipe made of a material with better corrosion resistance than aluminum alloy)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Takashi Kanazawa, Inventor 3-25-1, Tonomachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Isuzu Motor Co., Ltd. Kawasaki Factory (72) Inventor Tsugio Noro 3-chome Tonomachi, Kawasaki-ku, Kawasaki-shi No. 25 No. 1 Isuzu Motors, Ltd. Kawasaki Plant (56) References JP-A-4-166648 (JP, A) JP-A-59-170652 (JP, U) JP-A-55-4330 (JP, U) ( 58) Fields surveyed (Int.Cl. ⁷ , DB name) F02F 1/00-1/42

Claims (1)

(57) [Claims] A cooling water passage connected to a cooling water jacket through an inter-valve portion; a pipe made of a material having higher corrosion resistance than an aluminum alloy is inserted into the cooling water passage; An aluminum alloy cylinder head characterized in that a corrosion-resistant member made of the above material is provided at an outlet portion of the cylinder head to appropriately cover a casting surface.