JPS6140883Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine, and more particularly to a cylinder head structure for an engine with a fuel pump driven by a camshaft via a drive lever.

Conventionally, as shown in, for example, Japanese Utility Model Application Publication No. 54-27223, a fuel pump driven by a drive lever that swings in contact with an eccentric cam of a camshaft has been provided, and has been widely put into practical use. ing.

In a so-called OHC engine in which the camshaft is placed above the cylinder head, the fuel pump is mounted on the outer surface of the side wall at the top of the cylinder head, and the drive lever passes through a lever passage hole formed in this side wall and comes into contact with the eccentric cam. Generally, they are formed so that they touch each other.

On the other hand, lubricating oil is supplied to the valve train such as the camshaft and rocker arm, but in the OHC engine mentioned above, the lubricant oil supplied to the valve train is received by the upper surface of the cylinder head, and the lubricant oil is received by the cylinder head through an opening on the upper surface of the cylinder head. The oil is then returned to the oil pan via an oil pit that extends downward. If the valve train lubricating oil is received on the top surface of the cylinder head in this way, and the fuel pump is installed on the top of the cylinder head as described above, the lubricating oil will leak out from the fuel pump mounting area and cause the oil to leak onto the outside of the engine. Or it may stain the area around the engine. That is, the lubricating oil accumulated on the upper surface of the cylinder head flows to the fuel pump side through the drive lever passage hole of the cylinder head, and leaks from between the mounting seat of the fuel pump and the side wall of the cylinder head.

If the fuel pump is installed at a sufficiently high position so that the drive lever passage hole is higher than the lubricant accumulation level, the above disadvantages can be overcome.
Fuel pumps often cannot be mounted at such a high position due to the need to mount the cylinder head cover.

The present invention was developed in view of the above circumstances, and the purpose is to provide an engine cylinder head structure that does not cause the aforementioned lubricating oil leakage even when the fuel pump is installed at a normal height. That is.

The engine cylinder head structure of the present invention has an opening on the top surface of the cylinder head for returning oil in the cylinder head to the oil pan in an engine in which the above-mentioned fuel pump is installed on the outer surface of the side wall of the upper part of the cylinder head. It is characterized in that an oil drop hole extending downward is provided close to the side wall of the portion where the lever passage hole is provided.

If the oil drop hole is formed so as to be in contact with the side wall of the lever passage hole installation part as described above, the lubricating oil will not accumulate inside the lever passage hole, so the lubricating oil will pass through the lever passage hole. will not flow to the fuel pump side, and lubricating oil will not leak.

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

FIG. 1 shows a cylinder head structure of an engine according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line -2. A fuel pump 3 is mounted on the outer surface of the upper side wall 1a of the cylinder head 1 via a gasket 2. The fuel pump 3 is mounted by fastening its mounting seat 4 to the side wall 1a with bolts 5.

The fuel pump 3 has a diaphragm 7 that closes the open end of a cylindrical casing 6 with a bottom.
A rod 9 extending downward is fixed to the central portion. The space defined by the diaphragm 7 and the casing 6 is divided into upper and lower parts by a partition wall 10, each of which has check valves 11 and 12 that allow fuel to pass only in the direction of the arrow in FIG. is provided. The space above the partition wall 10 is divided into two chambers by a partition wall 13, each having check valves 11 and 12 at the bottom, and each partitioned chamber 14 and 15 has a suction pipe 16 and a suction pipe 16, respectively. A discharge pipe 17 is connected.

A drive lever 19 is disposed below the diaphragm 7 and is rotatably supported by a shaft 18 in the direction of arrow A in FIG. This drive lever 1
One end 19a of the rod 9 is in contact with the upper surface of the lower end 9a of the rod 9, which is urged upward by the spring 8. The other end 19b of this drive lever 19
extends above the cylinder head 1 through a lever passage hole 1b opened in the side wall 1a of the cylinder head where the mounting seat 4 is mounted. The drive lever 19 is urged clockwise by an arrow A in FIG. 2 by a spring 20, and the other end 19b
is in elastic contact with an eccentric cam 22 fixed to a camshaft 21 disposed above the cylinder head 1.

The cylinder head 1 has an oil drop hole 23 that opens on the upper surface 1c of the cylinder head and extends downward.
is provided. This oil drop hole 23 communicates with a similar oil drop hole provided in a cylinder block (not shown), and is ultimately led above an oil pan (not shown). As shown in FIG. 3, which is a cross-sectional view taken along the line 2 in FIG. A small hole 19c is provided at the bottom of the portion. A cylinder head cover 24 is attached to the upper part of the cylinder head 1.

The fuel pump 3 is commonly used for fuel transfer, and when the engine is rotated and the camshaft 21 rotates, the eccentric cam 2
The drive lever 19, which is in contact with the drive lever 2, reciprocates in the direction of arrow A in FIG. When the drive lever 19 reciprocates, the diaphragm 7 is moved up and down via the rod 9. When the diaphragm 7 is lowered, the lower part of the partition wall 10 becomes under negative pressure, and fuel is sucked into this part through the check valve 11. This fuel is
When the diaphragm 7 is then pushed upwards, it is pumped from the chamber 15 through the check valve 12 into the discharge pipe 17.

Lubricating oil is supplied to the camshaft 21 and the valve train including the rocker arm (not shown) by, for example, sprinkling it from the rocker arm or dispensing it from a small hole provided in the center of the camshaft 21. This lubricating oil is received by the upper surface 1c of the cylinder head 1 either by dripping from the valve train or by splashing and adhering to the cylinder head cover 24 and then dripping.

The lubricating oil received on the upper surface 1c of the cylinder head 1 as described above flows into the oil drop hole 23, flows down inside the oil drop hole 23, and is returned to the oil pan through the oil drop hole in the cylinder block. The lubricating oil received on the upper surface 1c of the cylinder head 1 may accumulate to some extent on the upper surface 1c of the cylinder head in a portion far from the oil pit 23, but as shown in the figure, this oil pit 23 Since the lever passage hole 1b is provided at a position in contact with the side wall 1a of the portion where the lever passage hole 1b is provided (that is, the inner surface of the side wall 1a constitutes a part of the peripheral wall of the oil drop hole 23), the side wall 1a of the lever passage hole 1b installation portion is provided. Lubricating oil will not accumulate along the Therefore, the lubricating oil does not flow out to the fuel pump 3 side through the lever passage hole 1b, and the lubricating oil is not leaked to the outside of the engine from between the mounting seat 4 of the fuel pump 3 and the side wall 1a of the cylinder head 1. No leakage.

Furthermore, as described above, the lubricating oil supplied to the valve train is scattered by the movement of the valve train, and a portion of it is received by the bottom surface of the gutter-shaped drive lever 19 with a U-shaped cross section. Since the oil flows out from the small hole 19c on the bottom of the drive lever 19, the lubricating oil flows to the fuel pump 3 side through the inside of the drive lever 19 and does not leak to the outside of the engine.

As described above in detail, the engine cylinder head structure of the present invention prevents leakage of valve train lubricating oil from the fuel pump mounting portion, and has the effect of keeping the outer surface of the engine and its surroundings clean.

[Brief explanation of the drawing]

Figure 1 is a plan view showing one embodiment of the present invention, Figure 2 is a plan view showing one embodiment of the present invention;
The figure is a cross-sectional view taken along the line -- in FIG. 1, and FIG. 3 is a cross-sectional view taken along the line -- in FIG. 1... Cylinder head, 1a... Cylinder head side wall, 1b... Lever passage hole, 1c... Cylinder head top surface, 3... Fuel pump, 19... Drive lever, 21... Camshaft, 22... Eccentric cam, 23...Oil pitfall.

Claims (1)

[Scope of utility model registration request] In an engine in which a fuel pump is installed on the outer surface of the side wall of the upper part of the cylinder head and has a drive lever that passes through a lever passage hole in the side wall and comes into contact with the eccentric cam of the camshaft, the fuel pump is used to return oil in the cylinder head to the oil pan. 1. A cylinder head structure for an engine, characterized in that an oil drop hole opening in the upper surface of the cylinder head and extending downward is provided close to a side wall of a portion where the lever passage hole is provided.