JPH0447373Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a rocker shaft that supports a rocker arm of an internal combustion engine for an automobile, for example.

Prior Art Figure 2 shows the overall configuration of a SOHC type gasoline engine and the lubricating oil distribution path to the lubrication system using a pressure-feeding system. In the figure, 1 is a cylinder book, 2 is a cylinder head, 3 is a rocker cover, and 4 is an oil pan.The lubricating oil pumped from this oil pan 4 by an oil pump 5 is transferred from an oil filter 6 to a main gear rally 7. Part of it lubricates the crankshaft 8, piston 9, etc., and part of it rises above the cylinder head 2 and passes through the rocker shaft 11, where it lubricates the bearing of the rocker arm 12 supported by the rocker shaft 11 and the camshaft 10. It is used to lubricate bearings or valve train systems such as the intake and exhaust valves 13, 13.

As shown in FIG. 3, the rock shaft 11 has an oil passage 15 with a circular cross section formed in the longitudinal direction of the main body 14 along the axis x direction, through which the lubricating oil flows. , is attached to the cylinder head 2 by a bolt 16 inserted perpendicularly to the axis x. Also, bolt 16
The shaft portion 17 has an outer diameter approximately the same as that of the oil passage 15, and a position corresponding to the oil passage 15 has a small diameter, and there is a space between the small diameter portion 17a and the inner wall of the oil passage 15. The formed arcuate passage 18,1
8 ensures the distribution of lubricating oil (Jitsukaisho
(See Publication No. 58-1704, etc.).

Problems to be Solved by the Invention Incidentally, the outer diameter of the rock shaft 11 is limited to a predetermined diameter or less because it affects the overall height of the engine, and the inner diameter of the oil passage 15 is also limited to the bending of the main body 14. The diameter is limited to a predetermined diameter or less in terms of rigidity and high-speed operation limit performance of the engine. Further, the outer diameter of the bolt 16, especially the outer diameter of the small diameter portion 17a, needs to be set small in order to ensure the passage cross-sectional area of the arcuate passages 18, 18. The reality is that it cannot be made sufficiently small because of the need to ensure bonding rigidity and strength. Therefore, the shaft portion 17 of the bolt 16, that is, the small diameter portion 17a, blocks most of the oil passage 15, which creates a large flow resistance for the lubricating oil and reduces the oil pressure in the oil passage 15. There is a problem in that lubricating oil cannot be sufficiently supplied to the valve train due to the drop in lubricating oil. In addition, 19 in the figure is Watshiya,
20 is a retainer that fixes the rocker arm 12.

Means for Solving the Problems This invention was devised in view of the above-mentioned problems of the conventional rock shaft. It is characterized by being carefully formed.

Effects According to this invention having the above configuration, the oil passage is located at a position offset from the position of the shaft of the bolt penetrating the main body, so that the lubricating oil in the oil passage has a flow resistance due to the shaft. It quickly circulates without being affected and is sufficiently supplied to the valve train.

Embodiment Hereinafter, an embodiment of this invention will be described in detail based on FIG. This embodiment is applied to a SOHC type gasoline engine, similar to the conventional ones shown in Figs. The same reference numerals are used for explanation.

In the figure, 2 is a cylinder head, 11 is a rocker shaft having the same outer diameter as the conventional rocker shaft, and a linear oil passage 21 is formed inside the rocker shaft body 14 in the longitudinal direction. This oil passage 21 has the same inner diameter as the conventional one, and its axis y is eccentric to the right side in the figure from the axis x of the rock shaft body 14.
4 over the entire lengthwise direction. Further, the rocker shaft 11 is attached to the cylinder head 2 by a bolt 16, and this bolt 16 is
A small diameter portion 17a is formed at a position corresponding to the passage 21 in the shaft portion 17, which has the same outer diameter as the conventional one. Furthermore, this shaft portion 17 penetrates through the rocker shaft 11 in a direction perpendicular to the axis x of the main body 14. Therefore, the oil passage 21 is
As shown in the figure, the right end portion largely protrudes from the side surface of the small diameter portion 17a, thereby creating a substantially semicircular cross section with a large passage cross-sectional area between the side surface of the small diameter portion 17a and the inner wall surface of the oil passage 21. A shaped flow path 22 is formed.

Therefore, according to this embodiment, the lubricating oil that has flowed into the oil passage 21 quickly flows through the flow passage 22 without being subjected to large flow resistance due to the small diameter portion 17a. A decrease in the oil pressure in the passage 21 is prevented, and a sufficient amount of lubricating oil can be supplied to the valve train.

Further, in the above embodiment, the entire oil passage 21 is eccentric from the axis x of the main body 14, but the bolt 1
It is also possible to make only the vicinity of the shaft portion 17 of No. 6 eccentric, and to make the rest concentric with the axis x as in the conventional case. In this way, by making the eccentric portion partial, it is possible to sufficiently ensure the bending rigidity of the rocker shaft 11, each part of which is subject to dimensional restrictions.

Effects of the invention As is clear from the above explanation, according to the internal combustion engine shaft according to this invention, the oil passage formed in the internal longitudinal direction of the main body is formed eccentrically from the axis of the main body, so that The lubricating oil in the oil passage quickly circulates without being subjected to large flow resistance due to the bolt passing through the main body. Therefore, a drop in the oil pressure in the oil passage is prevented, and a sufficient amount of lubricating oil can be supplied to the valve train. As a result, the bearings of the rocker arm and camshaft are prevented from seizing, and if equipped with a hydraulic valve lifter, air is prevented from entering the valve lifter, ensuring smooth and reliable operation of the valve train. can get.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a rock shaft of an internal combustion engine according to this invention, Fig. 2 is a perspective view showing the overall structure of the internal combustion engine and a lubricating oil distribution route, and Fig. 3 is a cross-sectional view showing a conventional rock shaft. It is. 2...Cylinder head, 11...Rock shaft, 14...Body, 16...Bolt, 17...Shaft portion, 15, 21...Oil passage, 22...Flow passage, x
...Axis center.

Claims (1)

[Scope of utility model registration request] In a rock shaft for an internal combustion engine that has an oil passage in the internal longitudinal direction of the body and is attached to the cylinder by a bolt inserted through the body, the oil passage is formed eccentrically from the axis of the body. The internal combustion engine is characterized by a rotsukashaft.