JP2002339713A - Lubricating structure in bearing device for camshaft of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure supply of sufficient lubricating oil to a sliding surface of the outer peripheral surface of a camshaft, in a bearing device where the camshaft 4 having a lubricating oil supply passage 5 in a cylinder head 2 is journalled to a bearing part 6 disposed in a cylinder head 3 and a bearing cap body 8 fastened to the bearing part, a through-hole 11 for passing a head bolt 3 for fastening the cylinder head to a cylinder block 1 is drilled in the bearing part 6, and an oil hole 12 is formed in the sliding surface supplied with the lubricating oil of the lubricating oil supply passage 5. SOLUTION: An opening 12a of the oil hole 12 to the outer peripheral surface of the camshaft is positioned in a place shifted from the center line 11a of the through-hole 11 in the bearing part 6 in the axial direction of the camshaft 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DOHC type internal combustion engine which supplies lubricating oil to a bearing device which rotatably supports a cam shaft for an intake valve or an exhaust valve with respect to a cylinder head thereof. It relates to a lubrication structure.

[0002]

2. Description of the Related Art Conventionally, when a camshaft is rotatably supported with respect to a cylinder head,
A bearing cap having a bearing hole into which a lower half of a camshaft having a lubricating oil supply passage fits, and a bearing cap body having a bearing hole into which the upper half of the camshaft fits. The bearing is lubricated with bolts, and when lubricating the bearing, an oil hole communicating with the lubricating oil supply passage inside the camshaft is opened on the outer periphery of the camshaft. By drilling, the lubricating oil in the lubricating oil supply passage is supplied to the sliding surface between the outer peripheral surface of the camshaft and the inner peripheral surface of each bearing hole surrounding the camshaft via this oil hole. (For example, Japanese Patent Application Laid-Open Nos. 10-18829 and
2-73731).

[0003]

By the way, in a recent internal combustion engine, a head bolt for fastening a cylinder head to a cylinder block is provided for supporting a cam shaft on the cylinder head. In this case, a through hole extending in the axial direction of the head bolt is formed in the bearing portion, and the head bolt is inserted and removed from the through hole. It is configured to do so.

Accordingly, in this configuration, the bearing hole in the bearing portion provided in the cylinder head is provided with a through hole for inserting and removing the head bolt. When applied, the oil hole communicates with the through hole for removing and inserting the head bolt over a long circumferential length during one rotation of the camshaft. The lubricating oil flows out more than the through-hole for insertion and removal of the head bolt, in other words, more lubricating oil flows out of the through-hole, and the outer peripheral surface of the cam shaft and the bearings surrounding it Since the lubricating oil supplied to the sliding surface with the inner peripheral surface of the hole is reduced, there is a problem that the lubricating oil cannot be sufficiently supplied to the sliding surface.

An object of the present invention is to solve this problem.

[0006]

SUMMARY OF THE INVENTION In order to achieve this technical object, the present invention provides a cylinder head, which is fastened to a cylinder block by a head bolt, and has a lower half of a camshaft provided with a lubricating oil supply passage therein. A bearing cap having a bearing hole into which the upper half of the camshaft fits is fastened to the bearing, and the head bolt is inserted into and removed from the bearing. The through hole is formed so that the through hole is opened in the bearing hole of the bearing portion. In a camshaft bearing device for an internal combustion engine having an oil hole formed so as to lead to a sliding surface with the inner surface of each of the surrounding bearing holes, an opening of the oil hole to an outer peripheral surface of the camshaft is provided. The bearing At a position that is displaced from the center line of the through hole in the axial direction of the camshaft and that the opening does not communicate with the through hole, or that a part of the opening communicates with the through hole. . "

[0007]

The lubricating oil in the lubricating oil supply passage in the camshaft is transferred between the outer peripheral surface of the camshaft and the inner peripheral surface of each bearing hole surrounding the camshaft via an oil hole formed in the camshaft. When supplying to the sliding surface, as described above, the opening of the oil hole to the outer peripheral surface of the cam shaft is shifted from the center of the through hole in the bearing in the axial direction of the cam shaft,
And, because the opening does not communicate with the through-hole, or because a part of the opening is located at a portion communicating with the through-hole, the oil hole is rotated during one rotation of the camshaft,
The area of the passage communicating with the through hole for removing and inserting the head bolt can be reduced, or the oil hole can be made not communicate with the through hole for inserting and removing the head bolt.

[0008] This makes it possible to reduce or eliminate the lubricating oil flowing out from the through hole for pulling out and inserting the head bolt, and to increase the lubricating oil that can be supplied to the sliding surface. As a result, a sufficient amount of lubricating oil can be reliably supplied.

In this case, as described in claim 2, according to claim 1, a portion of the inner surface of the bearing hole in the bearing portion other than the through hole for inserting and removing the head bolt, or the bearing cap. At least one oil groove communicating with the oil hole during rotation of the camshaft is provided on the inner surface of the bearing hole of the body so as to extend in the axial direction of the camshaft, and both ends of the oil groove are connected to the bearing portion or the bearing. By configuring so as not to communicate with the left and right surfaces of the cap body, the lubricating oil from the oil hole can be widely distributed over the entire sliding surface by the oil groove, so that the lubricity on the camshaft can be further improved. .

According to a third aspect of the present invention, in the second aspect, the oil is selected from one or both of the inner surface of the bearing hole in the bearing portion and the inner surface of the bearing hole in the bearing cap body. By providing an arc-shaped oil groove extending in the circumferential direction so as to communicate with the oil groove extending in the axial direction, at a portion corresponding to the opening of the cam shaft in the outer peripheral surface of the hole, the arc-shaped oil groove is formed. Since a large amount of lubricating oil from the oil hole can be collected and supplied to the oil groove extending in the axial direction,
The effect according to claim 2 can be further promoted.

[0011]

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

In this figure, 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 by a plurality of head bolts 3.
Reference numeral 4 denotes a camshaft for an intake valve or an exhaust valve disposed on the upper surface of the cylinder head 2, and a lubricating oil supply passage 5 into which lubricating oil is fed is provided inside the camshaft 4. I have.

A bearing 6 having a bearing hole 7 into which the lower half of the journal 4a of the camshaft 4 fits is provided integrally with the upper portion of the cylinder head 2. The camshaft 4 is rotatably supported by fastening a bearing cap body 8 having a bearing hole 9 into which the upper half of the journal part 4a fits with a pair of left and right bolts 10.

The head bolt 3 is disposed below the bearing 6, and a round through hole 11 for inserting and removing the head bolt 3 is formed in the bearing 6. It is pierced so that it does.

The journal portion 4a of the camshaft 4 is supplied with lubricating oil of the internal lubricating oil supply passage 5 of the camshaft 4 between the outer peripheral surface of the journal portion 4a and the bearing holes 7 and 9 surrounding the journal portion. Two oil holes 1 to be supplied to the sliding surface
Drill 2

In this case, the opening 12 is formed in the oil hole 12 with respect to the outer peripheral surface of the journal portion 4a.
a at a position shifted from the center line 11a of the head bolt insertion / removal through-hole 11 by an appropriate distance S in the axial direction of each shaft 4 and the opening 12a does not communicate with the through-hole 11, or Part of the opening 12a is a through hole 11
It is located at the site that communicates with

On the other hand, an oil groove 13 extending in the axial direction of the camshaft 4 is formed on the inner surface of the bearing hole 9 of the bearing cap body 8, and both ends of the oil groove 13 are provided on both left and right side surfaces 8a, 8b of the bearing cap body 8. Engraved so that it does not communicate with

In addition, an arc-shaped oil groove 14 extending in the circumferential direction is formed in a portion corresponding to the two oil holes 12 on the inner surface of the bearing hole 9 in the bearing cap body 8, and the oil groove extending in the axial direction. It is engraved so as to communicate with 13.

In this configuration, the lubricating oil in the lubricating oil supply passage 5 of the rotating camshaft 4 is supplied to the outer peripheral surface of the journal portion 4a of the camshaft 4 via the oil holes 12 and the bearing holes 7 surrounding the journal portion 4a. , 9 are supplied to the sliding surface.

In this case, the opening 12a to the outer peripheral surface of each of the oil holes 12 is formed at a portion of the bearing 6 which is shifted from the center line 11a of the through hole 11 by an appropriate distance S in the axial direction of the camshaft 4. Since a part of the opening 12a is located at a portion communicating with the through hole 11,
During the rotation of the camshaft 4, both oil holes 12
Since the passage area communicating with the head bolt insertion / removal through hole 11 can be reduced, the amount of lubricating oil flowing out from the head bolt extraction / removal through hole 11 is reduced, and the amount of lubricating oil supplied to the sliding surface is increased. it can.

The distance S from the center line 11a of the through hole 11 to the opening 12a of the oil hole 12 is preferably as large as possible, and most preferably, the distance S is as shown in FIG. The opening 1 of the oil hole 12
2a is set so as not to communicate with the through-hole 11, and the opening 12a of the oil hole 12 is configured so as not to communicate with the through-hole 11. Thereby, the lubricating oil flows through the through-hole 11 from the through-hole 11. Since no or little outflow is possible, the amount of lubricating oil that can be supplied to the sliding surface can be maximized.

An oil groove 13 extending in the axial direction is formed on the inner surface of the bearing hole 9 of the bearing cap body 8 so that both ends of the oil groove 13 do not communicate with the left and right side surfaces 8a and 8b of the bearing cap body 8. With this arrangement, the lubricating oil from the two oil holes 12 can be widely distributed by the oil grooves 13 over the entire sliding surface.

Further, an arc-shaped oil groove 14 extending in the circumferential direction is formed in a portion corresponding to the two oil holes 12 on the inner surface of the bearing hole 9 in the bearing cap body 8, and the oil groove 13 extending in the axial direction. The lubricating oil from both oil holes 12 can be collected in the two arc-shaped oil grooves 14 and supplied to the oil grooves 13 extending in the axial direction.

In the above-described embodiment, two oil holes 12 and two arc-shaped oil grooves 14 are provided. However, the present invention is not limited to this.
And one arc-shaped oil groove 14, and as shown in the figure, the oil groove 13 extending in the axial direction is provided instead of being provided on the bearing cap body 8 side.
The bearing hole 8 of the bearing portion 7 may be provided in a portion other than the through hole 11 opened in the bearing hole 8, that is, in a portion other than the through hole 11.

Further, the arc-shaped oil groove 14 and the oil groove 13 extending in the axial direction are preferably provided on the bearing cap body 8 side when the bearing load of the camshaft 4 on the bearing cap body 8 is large. When the bearing load of the camshaft 4 on the bearing portion 7 is large, it is preferable that the camshaft 4 be provided on the bearing portion 7 or that the camshaft 4 is provided so as to be annularly continuous with both the bearing cap body 8 and the bearing portion 7. Is also good.

The oil groove 13 extending in the axial direction is
It is preferable to provide it at a position on the rear side of the through hole 11 with respect to the rotation direction of the cam shaft 4.

[Brief description of the 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.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder head 3 Head bolt 4 Cam shaft 4a Journal part of cam shaft 5 Lubricating oil supply passage 6 Bearing part 7 Bearing hole 8 Bearing cap body 9 Bearing hole 11 Head bolt removal through hole 12 Oil hole 13 Oil groove 14 Arc shaped oil groove

Claims (3)

[Claims] A cylinder head fastened to a cylinder block by a head bolt is provided with a bearing having a bearing hole into which a lower half of a cam shaft having a lubricating oil supply passage is fitted. While fastening a bearing cap body having a bearing hole into which the upper half of the camshaft fits, the bearing portion is provided with a through hole for inserting and removing the head bolt,
The through hole is bored so as to open into a bearing hole in a bearing portion. Further, the camshaft is provided with lubricating oil in a lubricating oil supply passage therein and the outer peripheral surface of the camshaft and the bearing holes surrounding the camshaft. A camshaft bearing device for an internal combustion engine having an oil hole formed so as to be guided to a sliding surface with an inner surface of the camshaft, wherein an opening of the oil hole to an outer peripheral surface of the camshaft is penetrated by the bearing portion. It is characterized in that the opening is not communicated with the through-hole, or that a part of the opening is located in a position communicating with the through-hole at a position displaced from the center line of the hole in the axial direction of the camshaft. Lubrication structure in a camshaft bearing device of an internal combustion engine. 2. The camshaft according to claim 1, wherein a portion of the inner surface of the bearing hole in the bearing portion other than the through hole for inserting and removing the head bolt, or an inner surface of the bearing hole in the bearing cap body is provided. At least one oil groove through which the oil hole communicates during rotation is provided so as to extend in the axial direction of the camshaft, and both ends of the oil groove are configured not to communicate with the left and right surfaces of the bearing portion or the bearing cap body. A lubricating structure in a bearing device for a camshaft of an internal combustion engine, characterized in that: 3. The oil hole according to claim 2, wherein at least one of the inner surface of the bearing hole in the bearing portion and the inner surface of the bearing hole in the bearing cap body is connected to the outer peripheral surface of the cam shaft in the oil hole. A lubricating structure for a camshaft bearing device for an internal combustion engine, wherein an arc-shaped oil groove extending in a circumferential direction is provided at a portion corresponding to the opening so as to communicate with the oil groove extending in the axial direction.