JPS62294750A - Manufacture for cylinder head of internal combustion engine - Google Patents

Abstract

PURPOSE:To eliminate the necessity for using a core and to promote the improvement of castability of a cylinder head and its cooling performance and weight lightness resulting from the thin decrease of the thickness, by casting the cylinder head being vertically divided by a surface containing the upper bottom surface of a cooling water passage. CONSTITUTION:A cylinder head 23 is vertically divided by a surface containing he upper bottom surface of a cooling water passage 1, and the cylinder head 23, after its upper side part 3 and bottom side part 2 are cast in separate units, is integrally formed by welding. In this way, the cylinder head, in which the necessity of a core for molding the cooling water passage is eliminated, enables a casting defect to be prevented while thickness and weight to be decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method of manufacturing a cylinder head that constitutes an upper body of an internal combustion engine.

(Prior Art) Conventionally, cylinder heads for internal combustion engines are integrally formed by casting. FIG. 5 shows a type of engine in which the intake pulp and exhaust pulp (not shown) are driven directly by separate cams. As shown in the figure, the cast cylinder head 30 has an intake boat 8 and an exhaust boat 9 that open into the combustion chamber 10, and an intake pulp hole 21 and an exhaust pulp hole 22 that intersect with each bow. , a hole 2a29 for a pulp lifter located coaxially with the holes 21 and 22, a hole 16 for mounting the spark plug 6, and a cooling water passage 1 having a complicated shape so as not to interfere with these hole portions. is established.

(Problems to be Solved by the Invention) Recently, there has been a strong demand for automobile internal combustion engines to simultaneously satisfy both miniaturization and high performance.
In particular, are there any attached parts near the combustion chamber 10? Significant improvements have been made in terms of size and shape to enable additions. For this reason,
The cooling water t'ifi passage 1 is surrounded by the functional area as shown in the figure. The current situation is such that the shape is becoming more and more complex in the narrow space available, and the diameter has no choice but to be reduced.

As a result, the core for forming each cooling water channel 1 also becomes complicated and has a smaller diameter, leading to a decrease in residual dust. -y
llE 1m Silk 1-Yasuh Shishi Tof Reiki 1 Martyrby Yuko There is a problem that it is easy to get clogged.

In addition, since the diameter of the cooling water passage 1 becomes smaller,
This causes a problem in that the cooling performance in the vicinity of the combustion chamber 10 is significantly reduced, making knocking more likely to occur, and hindering the design of high-output internal combustion engines.

In view of the above-mentioned problems, the present invention is designed for use in internal combustion engines, which reduces the use of cores as much as possible by casting the cylinder head in parts, improves castability, and promotes cooling performance and weight reduction through thinner walls. The present invention aims to provide a method for manufacturing a cylinder head.

Means for Solving Problem C) The method of the present invention provides a method for solving problems in a cylinder head for an internal combustion engine.
Divided into two parts, upper and lower, using the upper bottom surface of the cooling water passage as a boundary.
The feature is that after each is cast in one separate process, the two are mutually polymerized and integrated by welding.

The cylinder head according to the present invention is usually constructed separately from the cylinder part, but when applied to a small internal combustion engine, it is also possible to cast the cylinder part integrally with the lower division body.

The cooling water passage, which is the divided part, is also located above the intake and exhaust boats. The reason why the surface including the upper inner wall of the cooling water passage is set as the dividing surface is because the lower surface of the upper parting body 1j is flat and can be easily cast without using a core. This is because L 71 can intersect with other functional parts such as an exhaust boat, and it can be easily integrated by welding.

In a gasoline engine, the above-mentioned cooling water passage is arranged around the spark plug section. Protrusions are provided on the spark plug part, the part where the intake and exhaust valves are located, the c-strip, and the lower division body.
A hole into which the projection iii fits is provided in the upper division body. The two upper and lower parts t11 are positioned relative to each other by fitting the protrusions and holes.n1 The end of the protrusion is welded to the upper part 41J.

The upper divided body and the lower divided body are manufactured by separate casting processes, and the cooling water passage is directly molded using a mold.

Thereafter, the two cast parts are stacked one on top of the other, and all seams are welded into one piece.

The reason why welding was chosen as the integration method is that it not only ensures liquid tightness at the divided parts of the cooling water passage, but also provides high joint strength, making it suitable for use as a cylinder head for high-output engines. This is because machining such as cutting is not required, and it can be easily converted into t-quantity using a robot or the like.

Although bolt connection may be considered as an integration method (for example, JP-A No. 55-29022), in this case, a special sealing member and a large number of bolts are required, resulting in a large number of parts. This requires multiple steps, and there is a concern that the strength of the integrated joint may loosen due to engine imaging.Moreover, cutting processes such as thread cutting must be performed, increasing the number of man-hours. It is easy to put into practical use in terms of production, cost, etc.

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In this case, the core is directly attached, eliminating the need for a core. Therefore, even when forming a cooling water passage with a complicated shape and a small diameter, there are no problems such as core breakage or core clogging, which are common in the past, and high pressure can be applied to the molten metal, improving quality and productivity. improves. The cooling rate of the molten metal on the molding surface increases and the molten metal flows better due to the application of high pressure, which significantly reduces casting defects and further improves quality.

With the reduction of casting defects, the structure of the inner surface of the cooling water passage is densified and its strength increases, promoting thinning of the wall, resulting in a significant overall weight reduction effect.

Furthermore, since the cylinder head structure can be made thinner, the opening area of the cooling water passage is substantially increased, and the distance between the cooling water passage and the combustion chamber is shortened accordingly. As a result, the combustion chamber wall surface temperature is reduced due to the improvement in cooling performance, and the occurrence of non-king, which is a problem in engine combustion, can be prevented, and engine performance can be improved.

At the time of casting, is it possible to prevent the core from floating, which was previously required? - Since there is no need to perform machining or plug tightening after casting, mass production can be carried out at low cost.

(Example) An example of the present invention will be described below with reference to FIGS. 1 to 4.

FIG. 1 is a cross-sectional view taken along line I-1 in FIG. 4, in which the cylinder head 23 is divided into two parts, a lower part 2 and an upper part 3, with a surface along the upper bottom surface of the cooling water passage 1 as the boundary. Both parts 2 and 31 are cast in separate processes, then overlapped and welded into one piece.

As shown in FIG. 1, the entire circumference of the abutting portion between the upper part 3 and the lower part 2 is welded, and 4 indicates this welded part. The upper protruding part of the spark plug 6 is protected by a hollow cylindrical protrusion 19 provided integrally with the lower part 2.The part where the protrusion 19 meets the upper part 3 is A circumferential weld 1 is applied, and 5 indicates this weld.Thus,
Sealing performance and high integration strength at the 6 portion of the spark plug are guaranteed.

In FIG. 1, reference numerals 8 and 9 are an intake boat and an exhaust boat formed on the lower part 2, and a combustion chamber 10 is provided on the lower surface side of the center of the lower part 2. Further, numerals 11 and 12 are threaded holes for attaching a cam journal and a cam cover formed in the upper part 3.

FIG. 2 is a cross-sectional view including the pulp attachment parts, and 14 indicates the portion where the suction/exhaust pulp is located.

The joining around the pulp 14 is performed by positioning and overlapping the upper part 3 with the pulp guide protrusion 18 provided on the lower part 2, and then joining the part around the protrusion 18 by welding. , 15 indicates this welded part, and in Fig. 2,
As specific forms of these welding parts 4.5.15, two welding forms are illustrated: concentrated heat source type beam welding and arc welding. The welded portion 4 on the outer surface of the cylinder head 23 is provided to ensure sealing performance as in FIG. 1.

FIG. 3 is a sectional view showing the tightening bolt, and the tf1h cylinder head tightening hole is a hole for the bolt, which is machined on the outer circumferential side of the lower part 2 so as not to interfere with the cooling water passage 1. It's cool. The welded portion 4 on the outer surface of the cylinder head 23 is provided to ensure sealing of the pulp portion as in FIG. 1.

FIG. 4 is an overall plan view showing the cylinder head 23 according to this embodiment, which is applied to an automobile gasoline engine having a sheave valve per cylinder. As shown in Fig. 1, the above-mentioned welding part 5 is provided around the ignition plug 6 of that part, and the above-mentioned welding part 15 is provided around the pulp part 14 of that part. I'm doing r. A welded portion 4 is provided on the outer surface of the cylinder head 23 over its entire circumference, thereby forming a cooling water passage 1 at the joint portion of the upper part 3 and lower part 2 of the cylinder head 23.
The sealing properties of the parts 3 and 2 are ensured, and the integral connection of both parts 3 and 2 is completely broken.

(Effects of the Invention) As described above, according to the present invention, the cooling water passage is prevented, and the cylinder head is made more movable and dangerous compared to the conventional method1. It has the effect of preventing non-king and promoting higher engine output.

[Brief explanation of the drawing]

FIGS. 1 to 4 show cylinder heads according to the present invention, and FIGS. 1, 2, and 3 are shown in FIGS.
4 is a cross-sectional view taken along the I-1 line, ■--■ line, and ■--■ line in FIG. 1...Cooling water passage 2...Lower part 3...Upper part 4.5.15...Welding part 23...Cylinder head patent application 1.1 Person Toyota Motor Corporation Fang 4 Figure Figure 25

Claims (1)

[Claims] Manufacture of a cylinder head for an internal combustion engine, characterized in that the cylinder head is divided into upper and lower parts on a plane including the upper bottom surface of a cooling water passage, and then the two cast parts are stacked and integrated by welding. Method.