JPS6293407A - Camshaft pivotably supporting structure for internal combustion engine - Google Patents

Abstract

PURPOSE:To enhance the rigidity of cam holders and to lessen the thermal expansion for preventing the occurrence of noise, by making the camshaft bearing parts of iron alloy, in a camshaft pivotably supporting device in which a cylinder head and cam holders are made of aluminium alloy. CONSTITUTION:When cam bearing parts are provided on a cylinder head 2 made of aluminum alloy, cam-holder side cam bearing parts 4 made of iron alloy are provided so as to oppose to cylinder-head side cam bearing parts 3, and on the upper part thereon an oil supply pipe 8 provided with an oil passage 10 is put on, and then it is fastened to the cylinder head 2 integrally with the cam bearing parts 4 by means of bolts 9. Since the large force acting on cams faces upward, by manufacturing the cam-holder side cam bearing parts 4 with iron materials, the strength can be increased and further the heat expansion can be lessened, and accordingly the increase in the bore of cam bearing can be reduced and noise can be lessened.

Description

[Detailed Description of the Invention] L1 Kaminatsu ■ Sarasho J The present invention relates to a camshaft support structure for an internal combustion engine in which the cylinder head and cam holder are made of a new aluminum alloy to reduce weight. be.

Support 1" 72 ji [-sweet y Σ-" Komari 2 rise Ll Sen- Sai ni-' Zee J (2 Σ"K 1 ni and the same ~) inferior X cylinder head and cam holder made of aluminum alloy In conventional internal combustion engines, the number of valves per cylinder increases, speeds increase (W), and when a hydraulic lash core adjuster is used, the bearing load applied from the tappet to the cam holder via the camshaft increases. The cam holder made of aluminum alloy, which has a relatively low elastic modulus, undergoes elastic deformation. In addition, aluminum alloy has a larger coefficient of thermal expansion than cast iron, which is the constituent material of the camshaft, so when the cylinder head is heated to a high temperature during operation, the cam holder's shaft expands. It's true.

Due to these causes, when the engine is running, the force l\shaft bearing eccentricity M increases, which causes noise and reduces durability. Inferior.

Gap straight A-mutual. (1 round 1 table length car 1 cho dan Ii 1 [smashing]
The present invention relates to an improvement of the camshaft X/foot pivot structure of an internal combustion engine that overcomes these difficulties, and is directed to an improvement of the camshaft X/foot pivot structure for an internal combustion engine equipped with an aluminum alloy cylinder head and a cam holder made of a aluminum alloy. (-1) The cam bearing part of the aluminum L-m alloy cam holder is made of iron to increase the rigidity of the cam holder, reduce its elastic deformation, and reduce thermal expansion during engine operation. Can be made smaller.

An embodiment of the present invention illustrated in FIGS. 1 to 4 will be described below.

The cylinder head 2 of the automobile gasoline engine 1 is made of aluminum alloy, and the top of the cylinder head 2 has a semi-cylindrical head side cam bearing part 3 having a certain number 11.
has been formed.

Additionally, cast iron cam holder side cam bearings 4 are placed separately above the head side cam bearings 3 of the cylinder head 2 with the camshaft 13 in between, and above these are mounted an integral aluminum plate. A cam holder connecting member 5 made of an alloy is placed thereon, and the cam holder side cam bearing portion 4 and the cam holder connecting member 5 are collinear and integrally attached to the head side cam bearing portion 3 by means of pins 1-0.

Thus, the asymptotic cam holder connecting member 5 includes a presser portion 6 that contacts the cam holder side cam bearing portion 4, a reinforcing connecting member 7 that connects the presser foot 3 and the portion 6 to the phase Lj, and the oil supply pipe portion 8 and the body JJ. Therefore, the oil passage 10 in the oil supply pipe portion 8 passes through the cam holder side cam bearing section 4 and the head side cam bearing section 3 (oil passage 11.1).
2) to a discharge port of an oil pump (not shown), and the oil supply pipe section 8 is connected to a cam shirt 1-13.
An oil passage 10 is connected to a position corresponding to the cam 14, and an oil discharge hole 15 directed toward the cam 14 is communicated with the oil passage 10.

Since the embodiment shown in FIGS. 1 to 4 is configured as described above, the automobile gasoline engine 1 is in operation, the cam shirt 1-13 and the oil pump (not shown) are rotationally driven, and the oil is The lubricating oil discharged from the pump passes through the oil passage 12.11.10 and is injected from the A-il outlet hole 15 toward the cam 14, so that the cam 14 is lubricated.

A large front wheel facing 10 is applied to the camshaft 13 due to the pressure from the arm 16 placed 1ζ from the cam 14, but the cam bearing 4 on the cam holder side, which internally bears this improvement, is made of cast iron. Because it is made of aluminum, it does not undergo elastic deformation like aluminum alloys.

Furthermore, when the automobile gasoline engine 1 is operated at high speed or for a long time, no matter which of the contact surfaces of the head side cam bearing section 3, the camshaft side cam bearing section 4, and the camshafts 71 to 13 are heated to a high temperature, the cam holder side cam bearing section 4 is made of cast iron and does not undergo large thermal expansion unlike aluminum alloy.

Therefore, the bearing eccentricity of the camshaft 13 with respect to the head side cam bearing section 3 and the cam holder side cam bearing section 4 is small, noise and vibration are low, and the cam holder side cam bearing section 4 is less likely to wear out. Improves durability.

Further, since the cam holder side cam bearing portions 4 are integrally connected to each other by the cam holder connecting member 5, the bearing portion of the camshaft 13 has high rigidity despite being lightweight.

In the embodiment shown in FIGS. 1 to 4, the cam holder side cam bearing portions 4 are each separated separately.
This may be constructed integrally as shown in the figure.

As described above, in the present invention, the rigidity of the cam holder is increased, the amount of elastic deformation thereof is reduced, and the thermal expansion is also reduced. Suppressing the increase in camshaft bearing eccentricity
, the noise Rp can be lowered, and the durability can be improved by 1.

[Brief explanation of drawings]

FIG. 1 is a perspective view illustrating an embodiment of a camshaft throat pivot structure for an internal combustion engine according to the present invention, and FIGS. 2 and 3 are cut along lines ll-Tl and mm in FIG. 1. Crossing ■
4 is a vertical sectional side view cut along the TV--TV line in FIG. 1, and FIG. 5 is a perspective view of another embodiment. DESCRIPTION OF SYMBOLS 1... Automatic heavy duty gasoline engine, 2... Cylinder head, 3... Head side cam bearing part, 4... Cam holder side cam bearing part, 5... Cam holder connection member, 6...
... Holding part, 7... Reinforcement connecting member, 8... Oil supply pipe part, 9... Bolt, 10... Oil passage,
11... Oil passage, 12... Oil passage, 13.
...Cam shirt], 14...Rikimu, 15...Oikawa Izumi, 16...Rocker arm.

Claims (2)

[Claims] (1) In an internal combustion engine equipped with an aluminum alloy cylinder head and an aluminum alloy cam holder,
A camshaft pivot structure for an internal combustion engine, characterized in that a cam bearing part of the aluminum alloy cam holder is made of iron. (2) A camshaft pivot structure for an internal combustion engine according to claim 1, wherein a plurality of cam holders arranged along the axial direction of the camshaft are integrally connected by an aluminum alloy part.