JPH07279638A - Lubricating device for cam shaft bearing part in dohc type internal combustion engine - Google Patents

Abstract

PURPOSE:To surely distribute and supply lubricating oil to the respective bearing parts for an intake part cam shaft 3 and the respective bearing parts for an exhaust valve cam shaft 7 in a DOHC type internal combustion engine in a simple construction. CONSTITUTION:A lubricating oil distribution path 16 communicated with a lubricating oil supply groove 13 of each bearing cap body of an intake valve cam shaft and with a lubricating oil supply groove of each bearing cap body of an exhaust valve cam shaft is provided on a first connecting part 1 for integrally connecting each bearing cap body 5 of the intake valve cam shaft to each bearing cap body 7 of the exhaust valve cam shaft. A lubricating oil supply path 17 to the lubricating oil distribution path in one first connecting part of the respective first connecting parts from a lubricating oil pump is bored in a cylinder head. A lubricating oil communicating path 19 for communicating the lubricating oil distribution paths with each other in each first connecting part is bored in a second connecting part 18 for connecting the respective first connecting parts to each other.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DOHC internal combustion engine in which both an intake valve cam shaft and an exhaust valve cam shaft are supported on the upper surface of a cylinder head. The present invention relates to a lubrication device for bearings.

2. Description of the Related Art Conventionally, in a DOHC type internal combustion engine, lubrication for bearings of both the intake valve cam shaft and the exhaust valve cam shaft has been performed inside both cam shafts in the axial direction. A lubricating oil passage extending is formed, and lubricating oil from a lubricating oil pump is introduced into the lubricating oil passage, and then distributed through the lubricating oil passage to each bearing portion (for example, See Japanese Utility Model Publication No. 2-69005).

When forming the lubricating oil passages inside the cam shafts, the cam shafts are simultaneously formed by casting when the cam shafts are manufactured by casting, and the cam shafts are formed. In some cases, the former process complicates the casting process, resulting in a significant increase in cost, and in the latter case, a long drill tool is used. Since the drilling process is difficult, the cost is also increased significantly. Moreover, in any case, since the lubricating oil passage is formed in the cam shaft so as to extend in the axial direction, the strength of the cam shaft is reduced. Therefore, the cam shaft must be thicker by this amount. It doesn't happen. Further, it has been proposed to form a lubricating oil passage in each of the bearing portions on the cylinder head side, but even in this case, a long drill tool must be used, resulting in a significant increase in cost. In addition, since the built-up portion for forming the lubricating oil passage must be provided inside the cylinder head, the structure of the cylinder head becomes complicated and the casting cost of the cylinder head increases. Become. The present invention is
A lubricating device capable of reliably supplying lubricating oil to each bearing portion of both camshafts in a DOHC internal combustion engine without forming a long lubricating oil passage inside the camshafts or in the cylinder head. It is a technical issue to provide.

In order to achieve this technical object, the present invention discloses that "a cam shaft for an intake valve is formed on a top surface of a cylinder head, and a plurality of bearing portions are integrally formed on the cylinder head. The cam cap for the exhaust valve is rotatably supported by the bearing caps for the bearings, and the camshaft for the exhaust valve is rotatably supported by the plurality of bearings integrally formed on the cylinder head and the bearing caps for the bearings. Consisting of DOH
In the C-type internal combustion engine, a first connecting portion is provided between each bearing cap body of the intake valve cam shaft and each bearing cap body of the exhaust valve cam shaft to integrally connect them. Lubrication that communicates with each of the first connecting portions to the lubricating oil supply groove on the inner surface of each bearing cap body of the intake valve cam shaft and the lubricating oil supply groove on the inner surface of each bearing cap body of the exhaust valve cam shaft. An oil distribution passage is provided, and a lubricating oil supply passage is formed in the cylinder head from the lubricating oil pump to the lubricating oil distribution passage at one of the first connecting portions. Second connecting portions that integrally connect the first connecting portions are provided between the first connecting portions, and the lubricating oil distribution passages of the first connecting portions are connected to the second connecting portions. The lubricating oil communication passage is bored. "."

[Operation] In this structure, the lubricating oil supplied from the lubricating oil pump through the lubricating oil supply passage to the lubricating oil distribution passage in the one first connecting portion is the intake air that is connected to each other by the one first connecting portion. At the same time as being distributed to the lubricating oil supply grooves on the inner surfaces of the bearing cap body of the valve camshaft and the bearing cap body of the exhaust valve camshaft, the other first oil is passed through the lubricating oil communication passage in the second connecting portion. After being supplied to the lubricating oil distribution passage in the connecting portion, the other first
Since the bearing cap body of the intake valve cam shaft and the exhaust valve cam shaft bearing cap body that are connected to each other at the connecting portion are distributed to the lubricating oil supply grooves on the inner surfaces of the bearing cap body,
Lubricating oil can be reliably supplied to each bearing portion for the intake valve cam shaft and each bearing portion for the exhaust valve cam shaft.

As described above, according to the present invention, it is possible to reliably supply the lubricating oil to each bearing portion for the intake valve cam shaft and each bearing portion for the exhaust valve cam shaft. Since it is not necessary to form a lubricating oil passage extending in the axial direction of each of the camshafts or to form a long lubricating oil passage in the cylinder head, it is possible to reduce the manufacturing cost of both camshafts and reduce the diameter. And the effect of being able to achieve simplification of the structure of the cylinder head.

Embodiments of the present invention will be described below with reference to the drawings. In the figure, reference numeral 1 indicates a plurality of cylinders 1a, 1b,
Reference numeral 2 denotes a cylinder block made of cast metal, which is fastened to the upper surface of the cylinder block 1 with a gasket 11 interposed therebetween. The upper surface of the cylinder head 2 has the cylinders 1a, The intake valve camshafts 3 in 1b and 1c are integrally formed on the upper surface of the cylinder head 2 at the positions of the cylinders 1a, 1b, and 1c. On the other hand, it is rotatably supported by a bearing cap body 5 fastened with a pair of bolts 6. Further, the cylinder head 2
On the upper surface of the cylinder 1, a cam shaft 7 for an exhaust valve in each of the cylinders 1a, 1b, 1c is integrally formed on the upper surface of the cylinder head 2 at a position of each of the cylinders 1a, 1b, 1c. 8 and a bearing cap body 9 fastened to each of the bearing portions 8 with a pair of bolts 10. Further, on the upper surface of the cylinder head 2, pipes 12 for mounting spark plugs are erected at the locations of the cylinders 1a, 1b, 1c. On the other hand, the bearing hole 5 of each bearing cap body 5 for the intake valve camshaft 3
Lubricating oil supply grooves 13 and 14 are engraved on the inner surface of a and the inner surface of the bearing hole 9a of each bearing cap body 9 for the exhaust valve cam shaft 7 so as to extend over a substantially semicircle. The bearing cap body 5 for the intake valve cam shaft 3 and the bearing cap body 9 for the exhaust valve cam shaft 7 are connected to the spark plug mounting pipe 1.
2 is integrally connected by a ring-shaped first connecting portion 15 so as to go around the outer periphery of the bearing 2, and the lower surface of each first connecting portion 15 is lubricated in the bearing cap body 5 with respect to the intake valve camshaft 3. A lubricating oil distribution passage 16 communicating with the oil supply groove 13 and the lubricating oil supply groove 14 in each bearing cap body 9 for the exhaust valve cam shaft 7 is formed. Further, the cylinder head 2 is provided with a lubricating oil supply passage 17 from a lubricating oil pump (not shown) on the cylinder block 1 side.
The lubricating oil supply passage 17 is provided so as to communicate with the lubricating oil distribution passage 16 in one of the first connecting portions 15 of the first connecting portion 15. On the other hand, the first connecting portions 15 are integrally connected to each other by the second connecting portions 18, and the first connecting portions 15 are connected in the second connecting portions 18.
A lubricating oil communication passage 19 is provided so as to communicate between the lubricating oil distribution passages 16 in FIG. In addition, each of the second
The connecting portion 18 is formed in a V-shaped bent shape so that the lubricating oil communication passage 19 inside thereof is drilled from the lower surface of the first connecting portion 15 at both ends of the second connecting portion 18 by drilling. It is configured so as to reduce the number of steps required to form the lubricating oil communication passage 19. Further, the bearing caps 5 for the intake valve cam shaft 3 are integrally connected to each other via a stay member 20 which also functions as a runner during casting, and for the exhaust valve cam shaft 7. The bearing caps 9 are integrally connected to each other via a stay member 21 that also serves as a runner during casting, which facilitates the casting of the bearing caps 5 and 7 at the same time. It is configured to ensure the strength and increase the strength of the bearing portion. In this case, by providing the stay members 20 and 21 on the outer side surfaces of the bearing cap bodies 5 and 9 as shown in FIG. Since it comes off from a position directly above, both cams (not shown) on both cam shafts 3 and 7 and both cams such as clearance adjustment between the valve lifter (not shown) with which the cam contacts There is an advantage that both the stay members 20 and 21 can be prevented from interfering with the maintenance of the shafts 3 and 7. With the above-described configuration, the lubricating oil from the lubricating oil pump is transferred to the first lubricating oil via the lubricating oil supply passage 17.
The bearing cap body 5 of the intake valve cam shaft 3 and the exhaust valve cam, which are supplied to the lubricating oil distribution passage 16 in the connecting portion 15 and then connected to each other from the lubricating oil distributing passage 16 by the one first connecting portion 15. It is distributed to the lubricating oil supply grooves 13 and 14 on the inner surface of the bearing cap body 7 of the shaft 7. On the other hand, the lubricating oil supplied to the lubricating oil distribution passage 16 in the one first connecting portion 15 passes through the lubricating oil communication passage 19 in the second connecting portion 18 and the lubricating oil in the other first connecting portion 15. Lubricating oil on the inner surface of the bearing cap body 5 of the intake valve camshaft 3 and the exhaust valve camshaft 7 that are supplied to the distribution passage 16 and then connected to each other at the first connecting portion 16 Supply grooves 13, 14
Therefore, the lubricating oil can be reliably supplied to the bearing portions for the intake valve cam shaft 3 and the bearing portions for the exhaust valve cam shaft 7. It should be noted that, as in the above-described embodiment, each first connecting portion 15 that connects the bearing cap body 5 of the intake valve cam shaft 3 and the bearing cap body 9 of the exhaust valve cam shaft 7 to each other is connected to the ring. And a structure in which the spark plug mounting pipe 12 is inserted thereinto, the first connecting portions 15 are
Spark plug mounting pipe 1 in each cylinder 1a, 1b, 1c
Since it can be disposed in the outer peripheral portion of the second connector 2, there is an advantage that an increase in space due to the provision of the respective first connecting portions 15 can be avoided. Also, the intake valve cam shaft 3
The rotation direction of the exhaust valve cam shaft 7 is indicated by arrows A and B in FIG.
By setting as described above, the introduction of the lubricating oil from the lubricating oil distribution passage 16 in the first connecting portion 15 into the lubricating oil supply grooves 13, 14 in both the bearing cap bodies 5, 9 is prevented. It can be accelerated by the rotation of 7.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a perspective view of a bearing cap body for both cam shafts when viewed from below.

FIG. 5 is a perspective view of a bearing cap body for both cam shafts when viewed from below in another embodiment.

[Explanation of symbols]

1 Cylinder Block 2 Cylinder Head 3 Intake Valve Cam Shaft 4 Bearing Part for Intake Valve Cam Shaft 5 Bearing Cap Body for Intake Valve Cam Shaft 7 Exhaust Valve Cam Shaft 8 Bearing Part for Exhaust Valve Cam Shaft 9 Exhaust Valve Bearing cap body for cam shaft 12 Spark plug mounting pipes 13, 14 Lubricating oil supply groove 15 First connecting portion 16 Lubricating oil distribution passage 17 Lubricating oil supply passage 18 Second connecting portion 19 Lubricating oil communicating passage

Claims (1)

[Claims] 1. A camshaft for an intake valve is rotatably supported on a top surface of a cylinder head by a plurality of bearing portions integrally formed on the cylinder head and a bearing cap body for each bearing portion, and an exhaust valve. A DOHC type internal combustion engine in which a camshaft for a vehicle is rotatably supported by a plurality of bearings integrally formed on a cylinder head and bearing caps for the bearings. A first connecting portion that integrally connects the cap body and each bearing cap body of the exhaust valve cam shaft is provided between the cap body and each of the bearing cap bodies of the exhaust valve cam shaft. A lubricating oil distribution passage communicating with the lubricating oil supply groove on the inner surface of each bearing cap body and the lubricating oil supply groove on the inner surface of each bearing cap body of the exhaust valve camshaft is provided, and the cylinder head is provided with a lubricating oil pump. While forming a lubricating oil supply passage to the lubricating oil distribution passage in one of the first connecting portions, the first connecting portions are integrally formed with each other between the first connecting portions. Second connecting portions are provided to connect with each other, and a lubricating oil communication passage is formed in each of the second connecting portions so as to communicate between the lubricating oil distribution passages in the first connecting portions. A lubricating device for a camshaft bearing in a DOHC type internal combustion engine.