JPH0599064A - Cylinder head of air cooled multiple cylinder overhead-valve engine - Google Patents

Abstract

PURPOSE:To provide a cylinder head of a multiple cylinder overhead valve engine constructed suitably for die casting. CONSTITUTION:In a cylinder head of a multiple cylinder overhead valve engine are disposed an intake port 12 on one side of the central center of the cylinder and an exhaust port 13 on the other side respectively. While the respective intake ports 12 are formed at the same angle to a line interconnection the centers of cylinders, the respective exhaust ports 13 are formed at the same angle to the line interconnecting the respective centers of cylinders. The respective intake ports 13 are formed to pass between push rods 11 corresponding to the respective cylinder. Thus, since the respective intake port and exhaust port forming molds can be extracted respectively in the same direction, the cylinder head can be formed by die casting.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder head of an air-cooled multi-cylinder overhead valve engine, and more particularly to an arrangement structure of intake ports and exhaust ports.

[0002]

2. Description of the Related Art Conventionally, in the manufacture of a cylinder head of an air-cooled multi-cylinder overhead valve engine, die casting, which is restricted by the shape of each part due to die cutting, has not been adopted, and a sand die which is easy to die is used. Casting was used. As a result, the shapes of the intake port and the exhaust port formed in the cylinder head could be designed relatively freely.

[0003]

However, in the case of casting using a sand mold, since the work after molding is troublesome and the dimensional accuracy of the finish is problematic, the mating surface and the like must be machined. Therefore, there is a problem that the number of manufacturing steps increases and the cost of parts increases. It is an object of the present invention to provide a structure of a cylinder head suitable for die casting, focusing on such a point.

[0004]

In order to achieve the above object, the present invention provides a cylinder head of an air-cooled multi-cylinder overhead valve engine having an intake port on one side and an exhaust port on the other side centered on the center of the cylinder. Arranged respectively, forming each intake port at the same angle with respect to the line connecting the cylinder centers, and forming each exhaust port at the same angle with respect to the line connecting the cylinder centers, It is characterized in that each intake port is formed so as to pass between the push rods corresponding to each cylinder.

[0005]

According to the present invention, the cylinder head of the air-cooled multi-cylinder overhead valve engine is arranged with the intake port on one side and the exhaust port on the other with the cylinder center as the center, and each intake port is connected to the line connecting the cylinder centers. Since the exhaust ports are formed at the same angle with respect to each other, and the exhaust ports are formed at the same angle with respect to the line connecting the cylinder centers, the intake port forming mold and the exhaust port forming mold are formed. The molds can be drawn in the same direction, and the head block of a multi-cylinder engine can be formed by die casting.

[0006]

1 is a longitudinal sectional view of a main portion of a head block, FIG. 2 is a vertical sectional front view of a horizontal two-cylinder air-cooled engine, and FIG. 3 is a cross-sectional plan view thereof. In this engine, a cylinder block portion (2) is integrally formed laterally from a crankcase (1), and two cylinders (3) are arranged in the cylinder block portion (2) so as to be arranged side by side.
The head block (4) is fixed to one end of (2), and the crankshaft (5) is arranged in the crankcase (1) in a front-rear penetrating manner.

The head block (4) has an intake valve for each cylinder.
(6) and the exhaust valve (7) are arranged, and the intake valve (6) and the exhaust valve (7) are the rocker arm chamber of the head block (4).
It is designed to be opened and closed by a rocker arm (9) arranged in (8). The rocker arm (9) is configured to open and close by swinging the push rod (11) driven by the valve operating cam shaft (10) interlocking with the crank shaft (5).

As shown in FIGS. 1 and 4, the head block (4) is provided with an intake port (12) at an upper part and an exhaust port (13) at an oblique lower position with the cylinder center as a center. I am doing it. And this intake port (12)
Are formed in such a manner that they intersect at a certain angle in a side view with respect to the line connecting the cylinder centers so as to pass between the intake / exhaust valve driving push rods (11) arranged corresponding to each cylinder. .. Further, both exhaust ports (13) are formed in a state where their axial core lines are parallel to each other at a position close to the spark plug (14) arranged corresponding to each cylinder.

In the crankcase (1), the crankshaft
A valve cam shaft (10) and a balancer shaft (15) are arranged in parallel with (5), and these three shafts (5), (10) and (15) are interlocked by a timed transmission gear mechanism (16). I am doing it. Also, the crankcase (1)
The bottom opening (17) of the is closed by the oil pan (18),
An oil strainer (20) is arranged in a lubricating oil storage chamber (19) in the oil pan (18).

When the cylinder head of the multi-cylinder overhead valve engine is constructed in this way, the molds for forming the intake ports (12) and the exhaust ports (13) can be removed in the same direction. The cylinder head of a multi-cylinder overhead valve engine can be formed by die casting with high dimensional accuracy. Therefore, the number of machining points in the product after casting can be reduced.

[0011]

According to the present invention, the cylinder head of the air-cooled multi-cylinder overhead valve engine is arranged with the intake port on one side and the exhaust port on the other with the center of the cylinder as the center, and connects the intake ports to the center of the cylinder. Since the exhaust ports are formed at the same angle with respect to the line, and the exhaust ports are formed at the same angle with respect to the line connecting the cylinder centers, the mold for forming the intake port and the exhaust port are formed. The molds can be pulled out in the same direction, and the head block of the multi-cylinder engine can be formed by die casting.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a main part of a head block.

FIG. 2 is a vertical sectional front view of a horizontal two-cylinder air-cooled engine.

FIG. 3 is a cross-sectional plan view of a horizontal two-cylinder air-cooled engine.

FIG. 4 is a vertical sectional front view of a main part of a head block.

[Explanation of symbols]

2 ... Cylinder block part, 3 ... Cylinder, 4 ... Head block, 11 ... Push rod, 12 ... Intake port,
13 ... Exhaust port.

Claims (1)

[Claims] 1. A head block (4) is fixed to a cylinder block portion (2) in which a plurality of cylinders (3) are arranged in series,
Intake port (12) and exhaust port corresponding to each cylinder (3)
In the cylinder head of an air-cooled multi-cylinder overhead valve engine in which (13) and (3) are formed in the head block (4), and cooling fins are projectingly provided on the head block (4), one of the intake ports is centered at the center of the cylinder. (12) and the exhaust port (13) on the other side.
2) is formed at the same angle with respect to the line connecting the cylinder centers, and each exhaust port (13) is formed at the same angle with respect to the line connecting the cylinder centers. A cylinder head for an air-cooled multi-cylinder overhead valve engine, characterized in that the port (13) is formed so as to pass between the push rods (11) corresponding to each cylinder.