JPH05209507A - Internal combustion engine - Google Patents

Abstract

PURPOSE:To stabilize oil feeding, carry out the sufficient oil feeding to the cam surface of a camshaft and prevent oil splashing from the cam. CONSTITUTION:A bracket 2 for supporting a camshaft 3 on a cylinder head 1 is provided with a cam cover 12 which covers the camshaft 3 and which has both an oil feeding passage 10 for feeding oil to the journal part 8 thereof and a small oil-feeding hole 11 for feeding oil to the cam surface 4a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine having an improved structure for supplying lubricating oil to a cam shaft provided on a cylinder head.

[0002]

2. Description of the Related Art In order to supply oil to a bearing portion and a cam surface (cam profile surface) of a cam shaft provided on a cylinder head for lubrication, a conventional internal combustion engine has a structure shown in FIG.
Or, the configuration as shown in FIG. 4 has been adopted. As shown in the figure, a cam shaft 3 is rotatably mounted on a cylinder head 1 of an internal combustion engine via a bracket 2, and a rocker arm 5 is swung by a cam 4 of the cam shaft 3 which is rotationally driven, so that a valve 6 is provided. It is designed to open and close.

A journal portion 8 is formed on the cam shaft 3,
These journal portions 8 are rotatably supported by bearings 9 formed on the bracket 2. The cylinder head 1 is provided with a main oil passage 13 for oil supply, and the main oil passage 13 is branched from the main oil passage 13 to supply oil to the journal portion 8 in each bracket 2.
0 is formed. Further, an oil supply passage 21 to which oil is supplied from the branch passage 20 is formed in the cam shaft 3 along the axial direction thereof, and an oil supply passage 21 branched from the oil supply passage 21 is opened to the cam surface 4a of each cam 4. The hole 22 is formed.

[0004]

However, in the above-mentioned internal combustion engine, since the oil passes through the camshaft 3, the oil supply becomes unstable under the influence of the centrifugal force. There was a problem. Further, not only is the oil scattered from the oil supply hole 22 by the centrifugal force and is not sufficiently supplied to the cam surface 4a, but also the scattered oil is sucked into the blow-by gas reduction device (PCV), which causes an increase in oil consumption and deterioration of emission. There was fear.

It has been proposed to provide a shielding plate to cover the cam in order to collect the oil scattered from the cam (Japanese Utility Model Laid-Open No. 59-163114), but the oil is not scattered from the cam. Not prevented.

Therefore, an object of the present invention is to provide stable oil supply, to supply sufficient oil not only to the journal portion of the camshaft but also to the cam surface, and to prevent the oil from scattering from the cam. The object is to provide an internal combustion engine that can

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a bracket for supporting a cam shaft on a cylinder head, the cam shaft being covered, and an oil supply passage and a cam for supplying oil to a journal portion thereof. It is characterized in that a cam cover having an oil supply small hole for supplying oil to the surface is provided.

[0008]

The oil is supplied to the journal portion of the cam shaft through the oil supply passage of the cam cover, and is also supplied to the cam surface from the small oil supply hole of the cam cover. In this way, the oil is supplied to each part without passing through the cam shaft, so it is not affected by the centrifugal force, the stability of oil supply can be achieved, and sufficient oil can be supplied to the cam surface. It will be possible. In addition, since oil is supplied to the cam surface from the small oil supply hole in the cam cover, unlike the case where oil is supplied to the cam surface from the oil supply hole that is opened in the cam surface, there is less oil splash, and even if oil is scattered This can be collected by the cam cover.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

1 and 2, reference numeral 1 denotes a cylinder head of an internal combustion engine, on which a cam shaft 3 is rotatably mounted via a bracket 2, and a cam of a cam shaft 3 which is rotationally driven. The rocker arm 5 is swung by 4 to open / close the valve 6. In the embodiment, one end of the rocker arm 5 is pivotally supported by a hydraulic lash adjuster (HLA) 7.

The cam shaft 3 includes a cam 4 and a journal portion 8
Are alternately formed, and these journal portions 8 are rotatably supported by bearings 9 formed on the bracket 2. The bracket 2 is provided with a cam cover 12 having an inverted U-shaped cross section, which covers the cam shaft 3 and has an oil supply passage 10 for supplying oil to the journal portion 8 thereof and an oil supply small hole 11 for supplying oil to the cam surface 4a. It is provided. The cam cover 12 is preferably formed integrally with the bracket 2, but may be attached to the bracket 2 with a bolt.

A main oil passage 13 for oil supply is formed in the cylinder head 1, and the oil supply passage 10 is formed at the top of the cam cover 12 along the longitudinal direction thereof. In addition, 14 in FIG. 2 is an oil supply port to HLA. A communication passage 15 that communicates the main oil passage 13 and the oil supply passage 10 is formed inside the bracket 2 located at the center, and an annular groove 16 that surrounds the journal portion 8 of the camshaft 3 is formed in the middle of the communication passage 15. Is installed.

The oil supply passage 10 has branch passages 17 for supplying oil to the journal portion 8, and these branch passages 17 are formed in the bracket 2. Further, the small refueling hole 11 is formed in the cam cover 12 so as to face the cam surface 4a and branch downward from the refueling passage 10.

According to the internal combustion engine having the above structure, the oil is guided from the main oil passage 13 through the communication passage 15 to the oil supply passage 10 of the cam cover 12, and at that time, the journal supported by the central bracket 2 is used. Oil is supplied to the portion 8 by an annular groove 16 provided in the communication passage 15. Further, the refueling passage 10 is provided in the other journal portion 8.
Oil is supplied through the branch passage 17 from
Oil is injected and supplied from the small oil supply hole 11 to the cam surface 4a.

Since the oil is supplied to each part without passing through the camshaft 3 in this way, the stability of the oil supply can be achieved without being affected by the centrifugal force, and the journal part of the camshaft 3 can be achieved. Not only 8 but also the cam surface 4a can be sufficiently supplied with oil. Further, since the oil is injected and supplied to the cam surface 4a from the small oil supply hole 11 of the cam cover 12, unlike the case where the oil is supplied to the cam surface from the oil supply hole opened in the cam surface 4a, the oil is less scattered, and Even if the water scatters, it can be collected by the cam cover 12. Further, the rigidity of the bracket 2 is increased by the cam cover 12, and the cam noise can be reduced.

FIG. 3 shows another embodiment of the present invention. As shown in the figure, a main oil passage 13 is formed on one side of the cylinder head 1, and the main oil passage 13 communicates with one end of an oil supply passage 10 formed in the cam cover 12. Therefore, in the oil supply passage 10 of the cam cover 12, unlike the above-described embodiment, oil is supplied to the bracket 2
You will be guided directly without passing through. This refueling passage 10
In order to supply oil to each journal portion 8 of the camshaft 3 from the camshaft 3, the bracket 2 is formed with a communication passage 18 that communicates the oil supply passage 10 and the oil supply port 14 to each HLA. An annular groove 19 surrounding the journal portion 8 of the shaft 3 is provided. Further, the cam cover 12 is formed with an oil supply small hole 11 branched from the oil supply passage 10 so as to face each cam surface 4a.

According to the internal combustion engine of this embodiment, not only the same effects as those of the above-described embodiment are achieved, but the oil supply port 14 to the HLA is arranged downstream of the oil supply path, so Air bubbles contained in
It is easy to escape from the gap between the journal portion 8 and the bearing 9 and it is possible to supply the HLA with good oil with a low air bubble mixing ratio.

In the above embodiment, the oil supply passage 10 is provided only on the top of the cam cover 12, but the cam cover 1
2, the oil supply passages 10 are formed at appropriate positions, and the oil supply small holes 11 that branch from the oil supply passages 10 and face the cam surface 4a are formed, so that an optimum amount of oil is supplied from various directions without excess or deficiency. May be supplied to.

[0019]

In summary, according to the present invention, the oil is supplied to each portion without passing through the cam shaft, so that the stability of the oil supply can be improved without being affected by the centrifugal force. Sufficient oil can be supplied to the cam surface, and unlike the case where oil is supplied to the cam surface from the oil supply hole that opens on the cam surface, there is less oil splash, and even if oil is splashed, the cam cover ensures this. Can be collected at.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an internal combustion engine according to the present invention.

FIG. 2 is a cross-sectional view of the main parts of FIG.

FIG. 3 is a sectional view showing another embodiment of the present invention.

FIG. 4 is a sectional view showing an example of a conventional internal combustion engine.

5 is a cross-sectional view of the main parts of FIG.

[Explanation of symbols]

 1 Cylinder Head 2 Bracket 3 Cam Shaft 4a Cam Surface 8 Journal Section 10 Lubrication Passage 11 Lubrication Small Hole 12 Cam Cover

Claims (1)

[Claims] 1. A bracket for supporting a cam shaft on a cylinder head is provided with a cam cover which covers the cam shaft and has an oil supply passage for supplying oil to a journal portion and an oil supply small hole for supplying oil to a cam surface. An internal combustion engine characterized by the above.