JP2531392Y2 - Lubrication structure of overhead cam mechanism - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lubrication structure for lubricating a valve lifter and a cam in a direct acting overhead cam mechanism.

[0002]

2. Description of the Related Art In a direct-acting overhead cam mechanism in which a valve lifter is directly driven by a cam, as disclosed in, for example, Japanese Utility Model Laid-Open No. 59-103812 and Japanese Utility Model Laid-Open No. 1-141313, a camshaft is disclosed. The valve lifter and cam are lubricated with oil that has flowed out from the journal onto the top surface of the cylinder head.

Referring to FIG. 4, a cam shaft 23 is rotatably supported by a journal portion 22 provided on a cylinder head 21 and is urged to project and retreat to the upper surface of the cylinder head 21. The valve lifter 26 at the upper end of the intake valve 24 and the exhaust valve 25 is directly driven by the cam 27. The lubrication of the valve lifter 26 and the cam 27 is controlled by the journal portion 22 of the cam shaft 23.
It is configured to perform with oil that has flowed out as indicated by the arrow.

[0004]

However, in the lubricating structure as described above, oil flowing out of the journal portion 22 flows to the journal portion 22 with respect to the valve lifter 26 and the cam 27, particularly at the beginning of operation of the engine or at low speed operation. There is a problem in that the oil is supplied only to the near portion, and only one surface of the cam 27 is lubricated, for example, as shown by hatching in FIG.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a lubricating structure of an overhead cam mechanism capable of reliably lubricating the entire valve lifter and the cam even at an initial operation or at a low speed.

[0006]

SUMMARY OF THE INVENTION The present invention provides a lubrication structure for lubricating a valve lifter and a cam with oil flowing out from a journal portion of a camshaft in a direct acting overhead cam mechanism in which a valve lifter is directly driven by a cam. A mortar-shaped oil reservoir is formed around the guide hole of the valve lifter on the top surface of the cylinder head, and the oil flowing out of the oil reservoir from the journal of the camshaft is guided to the center of the oil reservoir in the axial direction of the camshaft. The guide means is formed on the upper surface of the cylinder head.

[0007]

According to the present invention, a mortar-shaped oil reservoir is formed around the guide hole of the valve lifter on the upper surface of the cylinder head, so that the oil flowing out of the journal and flowing into the oil reservoir is entirely around the valve lifter. The oil that has been distributed toward the oil sump, and the oil that has flowed out of the oil sump is also guided by the guide means, and flows into the center of the oil sump in the direction of the camshaft axis which is most easily distributed to the entire oil sump. Even during low-speed operation, the entire valve lifter and cam can be reliably lubricated.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

In FIG. 3, a camshaft 3 is rotatably supported by a journal 2 provided on a cylinder head 1. Reference numerals 4 and 5 denote an intake valve and an exhaust valve provided for each cylinder. A valve lifter 6 attached to the upper end of each of the valves 4 and 5 is provided with a guide hole 7 formed in an upper portion of the cylinder head 1 through a cylinder head 1. Is guided so as to be able to move back and forth with respect to the upper surface of. The valve lifters 6 are urged upward by a coil spring 8 and are in contact with cams 9 provided on the camshaft 3 corresponding to the valve lifters 6. According to the above configuration, the valve lifter 6 is directly driven by the cam 9 with the rotation of the camshaft 3.
Is driven up and down, and the intake port and the exhaust port are opened and closed by the intake valve 4 and the exhaust valve 5 at a predetermined timing.

[0010] Oil is supplied to the journal 2 through an oil passage (not shown) provided in the cylinder head 1, and the oil that has lubricated the journal 2 flows out from the side surface to the upper surface of the cylinder head 1 as indicated by an arrow. As shown in FIGS. 1 and 2, a mortar-shaped oil reservoir 10 is formed around the guide hole 7 on the upper surface of the cylinder head 1 so as to lubricate the valve lifter 6 and the cam 9 with the oil that has flowed out. . The inclination angle θ of the mortar-shaped oil reservoir 10 with respect to the upper surface of the cylinder head 1 is shown large in the figure for easy viewing, but is actually about 1 degree.

Further, a rib 11 is formed so as to protrude outward from the oil reservoir 10 in a diameter direction orthogonal to the axial direction of the camshaft 3, and extends from the journal portion 2 of the camshaft 3 to the outside of the oil reservoir 10. The oil that has flowed out is guided to the center of the oil reservoir 10 in the axial direction of the cam shaft. End 1 of rib 11 on guide hole 7 side
1a is cut off at an inclined surface as necessary so as not to interfere with the cam 9.

According to the above configuration, the mortar-shaped oil reservoir 10 is formed around the guide hole 7 of the valve lifter 6 on the upper surface of the cylinder head 1, so that the oil flowing out of the journal portion 2 enters the oil reservoir 10. It flows in and accumulates, and is distributed toward the entire circumference of the valve lifter 6.
The oil flowing out of the oil reservoir 10 is
The oil reservoir 10 is guided to the center of the oil reservoir 10 in the camshaft axial direction, so that the oil is quickly distributed to the entire oil reservoir 10. Therefore, the entire valve lifter 6 and the cam 9 are surely lubricated even at the beginning of operation or at the time of low-speed operation.

In the above-described embodiment, the oil flowing out of the oil reservoir 10 is supplied to the camshaft 3 of the oil reservoir 10.
Although an example in which the rib 11 is formed as a means for guiding to the center in the axial direction has been shown, a groove may be formed in the upper surface of the cylinder head 1 and the oil may be poured into the oil reservoir 10.

[0014]

According to the lubricating structure of the overhead cam mechanism of the present invention, a mortar-shaped oil reservoir is formed around the guide hole of the valve lifter on the upper surface of the cylinder head. The oil that has flowed into the oil reservoir can be distributed to the entire circumference of the valve lifter, and the oil that has flowed out of the oil reservoir is poured into the central portion of the oil reservoir in the cam shaft axial direction where the oil is most easily distributed to the entirety by the guide means. Therefore, the entire valve lifter and cam can be reliably lubricated even at the beginning of operation or at low speed operation.

[Brief description of the drawings]

FIG. 1 is a perspective view of a main part of an embodiment of a lubrication structure of an overhead cam mechanism according to the present invention.

FIG. 2 is a partial sectional front view of a main part of the embodiment.

FIG. 3 is a partial sectional front view of the embodiment.

FIG. 4 is a partial cross-sectional front view of a lubricating structure of a conventional overhead cam mechanism.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Journal part 3 Camshaft 6 Valve lifter 7 Guide hole 9 Cam 10 Oil reservoir 11 Rib

Claims (1)

(57) [Scope of request for utility model registration] 1. A lubricating structure for lubricating a valve lifter and a cam with oil flowing out from a journal of a camshaft in a direct-acting overhead cam mechanism that directly drives a valve lifter by a cam. A mortar-shaped oil reservoir is formed around the guide hole, and guide means for guiding oil flowing out of the oil reservoir from the journal of the camshaft to the center of the oil reservoir in the axial direction of the camshaft is provided on the upper surface of the cylinder head. A lubrication structure for an overhead cam mechanism, which is formed.