Variable valve device for internal combustion engine

Abstract

A variable valve device includes a camshaft which is rotatably provided in an internal combustion engine while having a cam, a rocker shaft which is arranged next to the camshaft, a valve which is driven by the cam, a cam follower rocker which is rotatably provided in the rocker shaft, and is rocked by following the cam, a valve drive rocker which is rotatably provided in the rocker shaft next to the cam follower rocker, and drives the valve, and a switching portion which be able to switch the valve drive rocker between a drive state and a non-drive state. Either a body of the cam follower rocker or a body of the valve drive rocker is made of an iron-based metal material, and the other body is made of a material different from the iron-based metal material, heat treatment being not required in the different material.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention.

FIG. 1 is a perspective view showing an engine on which a variable valve device according to a first embodiment of the invention is mounted;

FIG. 2 is a perspective view showing the whole of both inlet and exhaust variable valve devices of one of cylinders mounted on a left bank of the engine shown in FIG. 1;

FIG. 3 is a plan view showing the inlet and exhaust variable valve devices of the one cylinder shown in FIG. 2 when viewed from an arrow A of FIG. 2;

FIG. 4 is a plan view showing a layout of various cams of a camshaft;

FIG. 5 is a sectional view showing the variable valve device on the inlet side (low speed) when viewed from an arrow B of FIG. 3;

FIG. 6 is a sectional view showing the variable valve device on the inlet side (high speed) when viewed from an arrow C of FIG. 3;

FIG. 7 is a sectional view showing the variable valve device on the exhaust side when viewed from an arrow D of FIG. 3;

FIG. 8 is a sectional view showing a non-lift cam and a periphery thereof when viewed from an arrow E of FIG. 3;

FIG. 9 is a perspective view showing the whole of the variable valve device on the inlet side;

FIG. 10 is a perspective view showing a state in which the variable valve device on the inlet side is taken apart into a cam follower rocker and a valve drive rocker;

FIG. 11 is a perspective view showing the whole of the variable valve device on the exhaust side;

FIG. 12 is a perspective view showing a state in which the variable valve device on the exhaust side is taken apart into the cam follower rocker and the valve drive rocker;

FIG. 13 shows states of various valve lifts provided by the inlet and exhaust variable valve devices;

FIG. 14 is an exploded perspective view showing a main part of a variable valve device according to a second embodiment of the invention;

FIG. 15 is an exploded perspective view showing a main part of a variable valve device according to a third embodiment of the invention; and

FIG. 16 is perspective view showing a state in which a sleeve is taken apart from each cylinder of the valve drive rocker shown in FIG. 15.

Claims

1. A variable valve device for an internal combustion engine, the device comprising: a camshaft which is rotatably provided in an internal combustion engine while having a cam;a rocker shaft which is arranged next to the camshaft;a valve is driven by the cam;a cam follower rocker which is rotatably provided in the rocker shaft, and is rocked by following the cam;a valve drive rocker which is rotatably provided in the rocker shaft next to the cam follower rocker, and drives the valve, either a body of the cam follower rocker or a body of the valve drive rocker is made of an iron-based metal material, and the other body is made of a material different from the iron-based metal material, heat treatment being not required in the different material;a switching portion which be able to switch the valve drive rocker between a drive state and a non-drive state.

2. The variable valve device for the internal combustion engine according to claim 1, wherein the switching portion includes: a switching operation portion which is formed in the other body while having a cylinder and a piston, the cylinder being communicated with an oil passage of the rocker shaft, the piston being slidably inserted into the cylinder; andan abutment which is formed in one of the bodies while being able to abut on the piston by the slide of the piston, anda sleeve made of the iron-based metal material is provided in an inner surface of the cylinder.

3. The variable valve device for the internal combustion engine according to claim 2, wherein the different material is a non iron-based metal material.

4. The variable valve device for the internal combustion engine according to claim 3, wherein the non iron-based metal material is an aluminum material.

5. The variable valve device for the internal combustion engine according to claim 1, wherein the valve drive rocker includes: a boss which is rotatably supported by the rocker shaft on both sides in which the cam follower rocker is located therebetween;a pair of rocker arms comprising the arms extend linearly from the boss to the valve; anda connecting arm which connects the arms at end portions of the extended arms.

6. The variable valve device for the internal combustion engine according to claim 5, wherein the switching portion is able to switch a displacement of the cam follower rocker between transmission to the valve drive rocker and non-transmission to the valve drive rocker, and a part of the switching portion on the valve drive rocker side is provided in the connecting arm.

7. The variable valve device for the internal combustion engine according to claim 6, wherein the switching portion includes: a switching operation portion which has a cylinder and a piston, the cylinder being communicated with an oil passage provided in the rocker shaft, the piston being slidably inserted into the cylinder; andan abutment which be able to abut on the piston by the slide of the piston, andone of the switching operation portion and the abutment is provided in the connecting arm.