JP2003074321A - Return passage structure of lubricating oil in cam chamber of marine internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a return passage structure of lubricating oil in a cam chamber of a marine internal combustion engine which can recover the lubricating oil in the chamber smoothly to an oil pan even in rocking of a ship body. SOLUTION: A bottom wall of a cam chamber arranged in the upward of an oil pan is inclined larger than a rocking angle of a ship body, an oil drain hole is provided in the lowermost end of the inclined bottom wall, lubricating oil in the cam chamber can be recovered to the oil pan through the oil drain hole even when the ship body is swiveled.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cam chamber lubricating oil return passage structure capable of smoothly collecting lubricating oil in a cam chamber of a marine internal combustion engine to an oil pan. It is. FIG. 3 is a schematic vertical sectional front view of a cam chamber 91 formed in a cylinder block 90 in a conventional marine internal combustion engine. FIG. 4 is a perspective view of a core 95 used when the cam chamber 91 is formed by casting. In an internal combustion engine mounted on a ship, lubricating oil 93 in a cam chamber 91 disposed above an oil pan (not shown) is dropped into an oil pan from an oil drain hole 92 provided in a bottom wall 94 of the cam chamber 91. To collect. The oil drain hole 92 is formed by the projection 96 of the core 95 (FIG. 4) when the cylinder block 90 is formed by casting. By the way, if the hull always keeps the parallel state during the operation of the marine vessel, the lubricating oil 93 in the cam chamber 91 falls into the oil pan from the oil drain hole 92. The amount of the lubricating oil 93 accumulated in the cam chamber 91 per time becomes larger than the amount of the lubricating oil 93 falling from the oil drain hole 92, and the lubricating oil 93 accumulates in the cam chamber 91. Due to this, the amount of lubricating oil to be collected in the oil pan may be insufficient, and the circulation of the lubricating oil may be interrupted, making it difficult to supply sufficient lubricating oil to the camshaft. Accordingly, the present invention provides a cam chamber lubricating oil return passage for a marine internal combustion engine that can collect lubricating oil in a cam chamber to an oil pan without delay even when the hull swings. The task is to provide a structure. In order to solve the above-mentioned problems, according to the present invention, the bottom wall of the cam chamber disposed above the oil pan is inclined more than the swing angle of the hull, and the inclined wall is tilted. An oil drain hole is provided at the lowermost end of the bottom wall, and lubricating oil in the cam chamber can be recovered to the oil pan through the oil drain hole even when the hull swings. FIG. 1 is a schematic longitudinal sectional front view of a cylinder block 1 of a marine internal combustion engine embodying the present invention. FIG. 1 shows only the left side of the cylinder block 1 mainly from the cylinder center. A crankshaft 7 (shown as an axis) is arranged on the cylinder center line, and a cam chamber 2 is formed in a cylinder block 1 on the left side of the cylinder center. A main gallery 4 (main passage of lubricating oil) is formed below the cam chamber 2, and an upper wall of the main gallery 4 also serves as a bottom wall 6 of the cam chamber 2. As shown in FIG. 1, the bottom wall 6 is inclined downward to the right toward the center of the cylinder, and an oil drain hole 5 is formed at the lowermost end thereof. The oil drain hole 5 is formed by a protrusion 9 of a core 8 (used when the cylinder block 1 is cast-formed) shown in FIG. The upper surface (slope) of the bottom wall 6 in FIG. 1 is formed along the slope 10 of the core 8. The inclination angle r ₁ of the bottom wall 6 with respect to the horizontal plane is the swing angle r ₂ when the hull 100 swings in the direction indicated by the arrow A.
It is set to a larger angle r _1. When the hull 100 is swung in the direction of arrow A, the bottom wall 6 is closer horizontally, since the inclination angle r ₁ is larger than the swing angle r _2, lubricating oil in the cam chamber 2, when the swing of the hull ( Also at the time of rolling), it falls from the oil drain hole 5 and is collected in the oil pan 3. Incidentally, the hull 100 is swung in the arrow A direction opposite the inclination angle r ₁ is further increased in the bottom wall 6, the lubricating oil in the cam chamber 2 becomes easier to flow out from the oil drain hole 5 (falling) . The projection 9 and the inclined portion 10 are formed continuously. The protruding portion 9 of the core 8 is more robust than the protruding portion 96 of the conventional core 95 shown in FIG. Even if the thickness of the bottom wall 6 is increased, the oil drain hole 5 can be reliably formed. In addition, since the thickness of the bottom wall 6 is hardly restricted by the wall thickness, the layout in the cylinder block 1 can be freely changed. And can contribute to downsizing of the internal combustion engine. FIG. 1 shows an example in which the bottom wall 6 is cast using the core 8 shown in FIG. 2 so that the center of the cylinder is lower. Alternatively, the bottom wall 6 may be inclined so that the center of the cylinder becomes higher by using a core. According to the present invention, the bottom wall 6 of the cam chamber 2 is
Greater inclination than the swing angle r ₂ during swinging of the hull 100 is (inclination angle r _1), since the oil drain hole 5 is provided at the lowermost end of the bottom wall 6 inclined, oil even during oscillation of the hull 100 Hole 5
The lubricating oil in the cam chamber 2 can be recovered to the oil pan 3 via the oil pan, the lubricating oil can be smoothly circulated, and seizure of the camshaft can be reliably avoided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic vertical front view of a cylinder block of a marine internal combustion engine embodying the present invention. FIG. 2 is a perspective view of a core forming a cam chamber. FIG. 3 is a schematic vertical sectional front view of a cam chamber formed in a cylinder block of a conventional marine internal combustion engine. FIG. 4 is a perspective view of a core used when forming the cam chamber of FIG. 3; [Description of Signs] 1 Cylinder block 2 Cam chamber 3 Oil pan 4 Main gallery 5 Oil drain hole 6 Bottom wall 7 Crankshaft 8 Core 9 Projection 10 Inclined portion r ₁ Bottom wall inclination angle r ₂ Hull swing angle

Claims (1)

Claims: 1. A bottom wall of a cam chamber disposed above an oil pan is inclined more than a swing angle of a hull, and an oil drain hole is provided at a lowermost end of the inclined bottom wall. A lubricating oil return passage structure for a marine internal combustion engine, wherein lubricating oil in a cam chamber can be recovered to an oil pan via the oil drain hole even when the hull swings.