JP2570757Y2 - Camshaft bearing device for overhead camshaft type internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a bearing device for supporting a camshaft in an overhead camshaft type internal combustion engine with respect to a cylinder head.

[Conventional technology]

In a conventional bearing device for a camshaft in the overhead camshaft type internal combustion engine, a bearing portion for the camshaft is provided in a valve mechanism chamber on an upper surface of a cylinder head.
For example, as disclosed in Japanese Utility Model Application Laid-Open No. 63-75548 and the like, a device provided integrally with a wall member forming the periphery of the valve mechanism chamber is provided, for example, in Japanese Utility Model Application Laid-Open No. 63-26705. As described in the official gazette and the like, the bearing portion is provided integrally with a gap between the axial outer surface and the inner surface of a wall member that forms the periphery of the valve mechanism chamber. There are things.

[Problems to be solved by the invention]

However, forming the bearing portion for the camshaft integrally with the wall member forming the periphery of the valve mechanism chamber as in the former has an advantage that the rigidity of the bearing portion can be improved, Since the lubricating oil accumulated on the inner bottom surface in the valve mechanism chamber is prevented from flowing in the direction of the oil drop passage to the oil pan, the camshaft bearing portion provided integrally with the wall member prevents the lubricating oil from flowing. It is necessary to separately form a flow passage for lubricating oil in the room, and there is a problem that the shape of the cylinder head becomes complicated and the cylinder head becomes large.

On the other hand, by providing the bearing portion for the cam shaft integrally so as to leave a gap between the side surface thereof and the wall member forming the periphery of the valve operating mechanism chamber as in the latter case, it is necessary to provide a lubricant oil in this gap. On the other hand, it has the advantage of being able to form a flow passage of
The rigidity of the bearing portion and the wall member is reduced, and a part of the rotating camshaft is exposed in the valve operating mechanism chamber in the gap between the bearing portion and the wall member. Since the amount of oil mist generated in the valve mechanism chamber increases due to the splashing of the lubricating oil by the rotation of the camshaft in the exposed part, not only the amount of lubricating oil that disappears with the blow-by gas increases, but also There is a problem that the occurrence of oil leakage from the joint portion between the valve mechanism chamber and the head cover with respect to the valve mechanism chamber increases.

An object of the present invention is to provide a bearing device that solves all of these problems.

[Means for solving the problem]

In order to achieve this object, the present invention provides an overhead camshaft type internal combustion engine in which a camshaft for an intake valve and an exhaust valve is disposed in a valve mechanism chamber on the upper surface of a cylinder head. A bearing having a circular bearing hole into which one end of the camshaft fits by moving the camshaft in the axial direction is formed between the axially outer surface of the bearing and the periphery of the valve mechanism chamber. A gap for forming a flow passage of the lubricating oil so as to be continuous with an inner bottom surface of the valve mechanism chamber is provided between the bearing and the inner surface of the wall member to be formed; The upper surface of the outer part of the part
It is located at a position higher than the camshaft and is formed on a sealing surface for a head cover that covers the valve mechanism chamber, while partially covering the upper portion of the camshaft between the bearing portion and the wall member. And are integrally connected via a cover body configured as described above. "

[Actions and effects of the invention]

As described above, by providing a gap between the inner side surface of the wall member forming the periphery of the valve mechanism chamber and the axially outer side surface of the camshaft bearing portion, the lubricating oil The wall member, while the flow passage is formed such that the flow passage is continuous with the inner bottom surface of the valve mechanism chamber,
Since the bearing and the bearing can be integrally connected via the cover body, it is possible to prevent a decrease in the rigidity of the cylinder head due to a gap between the wall member and the bearing.

In this case, in addition to forming the upper surface of a portion of the wall member outside the bearing portion at a position higher than the camshaft and forming a sealing surface for a head cover that covers the valve mechanism chamber. Since the bearing portion and the outer wall member are integrally connected by a cover body, the portion of the wall member outside the bearing portion has high rigidity and is less likely to cause oil leakage. As a result, a reliable sealing surface can be secured.

Moreover, the camshaft in the gap between the wall member and the bearing portion is covered at its upper part with the cover body, and the lubricating oil jumping from the camshaft in the portion in the gap scatters into the valve train mechanism chamber. Can be prevented,
The generation of oil mist can be suppressed, the amount of lubricating oil that disappears together with the blow-by gas can be reliably reduced, and oil leakage from the joint with the head cover can be reliably prevented.

〔Example〕

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a cylinder block, and reference numeral 2 denotes a cylinder head fastened to a top surface of the cylinder block 1 with a plurality of head bolts 3. Each of the cylinder heads 2 has a combustion chamber 4 recessed in the lower surface thereof, and has an intake port 5 provided with an intake valve 6 and an exhaust port 7 provided with an exhaust valve 8. On the upper surface of the cylinder head 2, there is formed a valve mechanism chamber 9, which is surrounded by a wall member 10. The valve mechanism chamber 9 is formed on the upper surface of the wall member 10 around the cylinder head 2. It is hermetically sealed by a head cover 11 which is detachably attached to the head.

A camshaft 12 and a swing arm 13 for the intake valve 6 are provided in the valve mechanism chamber 9 of the cylinder head 2.
A valve mechanism 15 including a swing arm 14 and the like for the exhaust valve 8 is provided.

Further, the cylinder head 2 and the cylinder block 1 are provided with a lubricating oil that has accumulated on the inner bottom surface of the valve mechanism chamber 9 for flowing down to an oil pan (not shown) at a lower portion of the cylinder block 1. Oil drop passages 16a, 16
b is formed.

The camshaft 12 is provided on the inner bottom surface of the valve mechanism chamber 9.
A plurality of bearing portions 17a with circular bearing holes for
When the cam shaft 12 is supported by fitting the cam shaft 12 by moving the cam shaft 12 in the axial direction at the bearing portions 17a and 17b, the respective bearing portions 17a and 17b are provided.
a, 17b, the bearing portion 17a adjacent to the wall member 10,
An appropriate dimension (S) is formed between the axially outer surface of the bearing portion 17a and the inner bottom surface of the wall member 10, and the inner bottom surface of the valve mechanism chamber 9 is formed in the gap. Flow passage 18 for guiding the lubricating oil that accumulates in the oil drop passage 16a
Is formed so as to be continuous with the inner bottom surface of the valve mechanism chamber 9, and between the bearing portion 17 a and the wall member 10,
A cover body 19 configured to partially cover the upper portion of the cam shaft 12 is provided integrally.

In addition, an upper surface of a portion of the wall member 10 outside the bearing portion 17a is formed at a position higher than the camshaft 12 to form a sealing surface for the head cover 11 that covers the valve mechanism chamber 9.

Reference numeral 20 denotes a distributor mounted on the outer surface of the wall member 10 in the cylinder head 2, and the distributor 20 is connected to the camshaft 12 in the gap having the dimension (S).

With this configuration, the valve operating mechanism is provided between the inner surface of the wall member 10 forming the valve operating chamber 9 and the axially outer surface of the camshaft bearing 17a adjacent to the wall member 10. The wall member 10 and the bearing portion 17a are integrally connected by a cover body 19 while forming a lubricating oil flow passage 18 for guiding the lubricating oil accumulated on the inner bottom surface of the chamber 9 to the oil drop passage 16a. By doing so, the rigidity in this part can be improved, and the cover body 19
By covering a portion of the camshaft 12 between the wall member 10 and the bearing portion 17a, it is possible to prevent the lubricating oil that jumps up from a connection portion between the camshaft 12 and the distributor 20 in this portion from scattering into the valve mechanism chamber 9. It can be prevented.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention, FIG. 1 is a view showing the gist of the present invention, a sectional view taken along the line II of FIG. 2, FIG. 2 is a plan view of a cylinder head, and FIG. FIG. 4 is a sectional view taken along line III-III, and FIG. 4 is a sectional view taken along line IV-IV of FIG. DESCRIPTION OF SYMBOLS 1 ... Cylinder block, 2 ... Cylinder head, 4 ... Combustion chamber, 5 ... Intake port, 7 ... Exhaust port, 9 ... Valve operating chamber, 10 ... Wall member, 11 ... Head cover, 12 ... Camshaft, 15 ...
Valve operating mechanism, 16: Oil drop passage, 17a, 17b: Bearing, 1
8 ... Lubricating oil flow passage, 19 ... Cover body.

Claims (1)

(57) [Scope of request for utility model registration] 1. An overhead camshaft type internal combustion engine having a camshaft for an intake valve and an exhaust valve disposed in a valve mechanism chamber on an upper surface of a cylinder head, wherein one end of the camshaft is provided in the valve mechanism chamber. The bearing portion having a circular bearing hole into which the portion is fitted by the movement of the camshaft in the axial direction is provided with an axially outer surface of the bearing portion and an inner surface of a wall member forming a periphery of the valve mechanism chamber. And a gap for integrally forming a flow passage for lubricating oil between the inner bottom surface of the valve mechanism chamber and the upper surface of a portion of the wall member outside the bearing portion. Is located at a position higher than the camshaft and is formed on a sealing surface with respect to a head cover that covers the valve mechanism chamber, while the upper portion of the camshaft is partially formed between the bearing portion and the wall member. Configured to cover A bearing device for a camshaft in an overhead camshaft type internal combustion engine, wherein the bearing device is integrally connected via a cover body.