JPH0724569Y2 - Lubrication system for valve train in internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of the Invention The present invention mainly relates to a lubrication device for a valve operating system such as a valve arm portion in an overhead valve internal combustion engine.

2. Description of the Related Art Conventionally, in an overhead valve type internal combustion engine of this type, lubricating oil jumped up by a rotating part or the like in a crank chamber is supplied to a valve arm chamber side through a passage formed in a cylinder body. There is. In this case, the inlet on the crank chamber side of the passage is provided at a position where an appropriate amount of lubricating oil is supplied to the passage when the crankshaft is rotated in the forward direction. Therefore, in the case of an engine of a so-called reverse rotation type in which the crankshaft is rotated in the reverse direction, a larger amount of lubricating oil is supplied to this inlet side than in the case of normal rotation. However, there is a drawback that the pressure in the crank chamber rises and oil leaks from the oil seal portion or the governor yoke shaft portion of the crank shaft or cam shaft supported by the crank case. Further, this passage has a function of returning the oil to the crank chamber side even when a large amount of oil is accumulated in the cylinder head portion. However, when the oil is filled in the inlet portion as described above, such a function is performed. However, there is a disadvantage that the cylinder head is filled with a large amount of lubricating oil. Therefore, as a means for solving such a problem, two passages are formed in the cylinder body, one of which is a supply side to the valve arm chamber side, and the other is a return side, and these passages are always used. It may be possible to circulate the lubricating oil, for example, Japanese Utility Model Publication No. 61-41932 or
The 62-15451 publication describes such a thing.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in order to provide the two passages of the cylinder body as described above, the shape of the cylinder body has to be increased by that much, and the whole body is increased in size. Is produced by die casting,
There is a manufacturing problem that it is difficult to form long holes for such passages. The present invention aims to solve the above-mentioned inconvenience without forming two passages in the cylinder body.

Means for Solving the Problems In order to solve the above problems, the present invention is directed to an inclined engine in which a cylinder center line is inclined in an oblique direction, and a lubricating oil jumped up by a rotating portion in a crank chamber is used in a cylinder body. In the one that is supplied to the valve arm chamber on the upper side of the cylinder head through the passage formed in the above, in the peripheral portion of the inlet on the crank chamber side of the passage, communicates with the inlet,
Further, it is characterized in that a concave portion is formed which is eccentric to the one side of the inlet in the rotational direction of the crankshaft so as to allow a part of the oil to escape when the crankshaft rotates in the reverse direction.

Example FIG. 3 is a cross-sectional view of the entire engine taken along a vertical plane passing through a push rod insertion hole.
The engine of this embodiment is an inclined engine in which the center line of the cylinder is inclined. In the figure (1)
Is a cylinder body integrally provided with a crank chamber (2),
(3) is a cylinder head attached to the upper side of the cylinder body (1), and (4) is a valve arm chamber case that covers the valve arm chamber (5) above the cylinder head (3). (7)
Is a cylinder liner inserted in the cylinder body (1), (8) is a piston, (9) is a crankshaft, (10)
Shows a connecting rod connecting the crankshaft (9) and the piston (8). A push rod (12) and a tappet (13) are inserted into a push rod insertion hole (11) formed in parallel with the cylinder liner (7) and below the cylinder liner (7), and the tappet (13) is inserted. The lower end of the shaft contacts the cam (15) on the cam shaft (14) pivotally supported in the crank chamber (2). The push rod (12) is located in the valve arm chamber (5).
It abuts on the inner valve arm (16), and through this valve arm (16),
The intake / exhaust valves (17) (17) are driven. Then, between the pair of push rod insertion holes (11) (11) for the intake / exhaust valves (17) (17), in parallel with the push rod insertion holes (11) (11), the lubricating oil supply passage ( 18)
It is formed from the crank chamber (2) side through the cylinder head (3) toward the valve arm chamber (5) side. Lubricating oil splashed up by the flip-up plate (19) mounted on the crankshaft (9) hits the crankshaft (9) or other rotating parts such as the camshaft (14) directly, and their The particles are scattered by the rotating part and supplied to the inlet side of the passage (18). Then, it is supplied to the valve arm chamber (5) side through the passage (18) to lubricate the contact portion between the valve arm (16) and the push rod (12) and other sliding portions. Further, the oil mist and blow-by gas in the crank chamber (2) enter the valve arm chamber (5) side from the passage (18) due to the increase in internal pressure when the piston (8) descends. In the valve arm chamber (5), a breather (21) having a check valve (20) is attached to the case (4) portion as shown in FIG. Is supplied from the breather (21) to the intake passage side before the carburetor (22) and is reused as combustion gas.

In the above engine, when the crankshaft (9) rotates in the direction of arrow B in FIG. 1, it is a positive rotation, and in this case, the rotation direction of the flip-up plate (19) is also the inlet of the passage (18). Since a large amount of lubricating oil is rotated in the direction away from the passage (18)
However, in the case of reverse rotation specifications,
Since the flip-up plate (19) rotates toward the inlet side of the passageway (18), a large amount of lubricating oil fills the inlet portion. Therefore, in this embodiment, as shown in FIG. 1 and FIG. 2, a crank chamber inner wall (23) communicating with the inlet (18) and having the inlet is provided at one location around the inlet of the passage (18). ) Groove-shaped recess (25) opened to the side of
Is formed eccentrically with respect to the inlet (18) in one of the rotation directions of the crankshaft (9), that is, in the forward rotation direction.
Even if a large amount of lubricating oil is scattered on the inlet side of the passage (18) in the case of the reverse rotation specification, the lubricating oil is allowed to escape to this recess (25) side, preventing the inlet from being filled with lubricating oil. I am trying to do it. As a result, even in the case of the reverse rotation type, the inlet of the passage (18) is filled with lubricating oil,
It is possible to prevent oil leakage due to an increase in the internal pressure of the crank chamber (2) and filling of the cylinder head (3) with lubricating oil.

As described above, according to the present invention, the concave portion around the passage inlet can prevent the inlet from being filled with the lubricating oil, thereby preventing the oil leakage and the filling of the lubricating oil in the cylinder head portion. The present invention has a simple structure in which the recess is eccentrically formed in one of the crankshaft rotation directions, and two passages are provided to distinguish the supply side and the return side as in the conventional case. Compared with, there is an effect that it is compact as a whole and can be easily formed even in the case of production by die casting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a main part of a cylinder body showing an embodiment of the present invention, FIG. 2 is a front view when viewed from the direction A in FIG. 1, and FIG. 3 is an engine. FIG. 4 is a longitudinal sectional view of the whole, and FIG. 4 is a lateral sectional view of an essential part taken along the line AA in FIG. (1) …… Cylinder body, (2) …… Crank chamber,
(3) …… Cylinder head, (5) …… Valve arm chamber, (18)
...... passage, (25) ...... recess.

Claims (1)

[Scope of utility model registration request] 1. A tilted engine having a cylinder centerline tilted in an oblique direction, wherein a valve arm on an upper side of a cylinder head is provided through a passage formed in a cylinder body of lubricating oil that is lifted up by a rotating portion in a crank chamber. In the case where the crankshaft is supplied to the chamber, the passage is communicated with the inlet in the vicinity of the crank chamber side of the passage, and is eccentric to one side of the inlet in the direction of rotation of the crankshaft so that the crankshaft rotates in the opposite direction. In the above case, a lubrication device for a valve train in an internal combustion engine is characterized in that a recess is formed to allow a part of oil to escape.