Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2000-08-30
2001-11-13
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C074S56800M, C464S002000, C464S160000
Reexamination Certificate
active
06314929
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a valve timing control device of an internal combustion engine, that controls or changes open/close timing of intake or exhaust valves under operation of the engine.
2. Description of the Prior Art
Some of the valve timing control devices are of a type that is arranged between a sprocket that is driven by a timing chain in synchronization with the engine rotation and a camshaft that drives intake valves or exhaust valves and arranged to rotate the camshaft in one or the other direction relative to the sprocket thereby to control or change the open/close timing of the valves.
Japanese Patent First Provisional Publication
9-324611
shows a valve timing control device which comprises a sprocket driven by a timing chain in synchronization with the engine rotation, a housing rotated together with the sprocket, a rotor installed in the housing and rotated together with a camshaft, a plurality of radially outward projecting vanes provided on the rotor in a manner to define in the housing a plurality of working fluid chambers and a charging/discharging means for charging and discharging a working fluid to and from the working fluid chambers. By actuating the charging/discharging means, a relative rotation is induced between the housing and the rotor and thus between the camshaft and the sprocket. The sprocket is integral with the housing and they are made of cast iron. The sprocket has on its outer periphery a plurality of teeth with which the timing chain is meshed.
For lubricating the sprocket and the timing chain, the lubrication oil in an oil pan is used. That is, due to rotation of a crankshaft of the engine, the oil in the oil pan is splashed over the sprocket and the timing chain. However, this oil application method has failed to obtain satisfied oil lubrication at the portion where the sprocket and the timing chain are meshed.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a valve timing control device of an internal combustion engine, which assures satisfied oil lubrication at the portion where the sprocket and the timing chain are meshed.
According to a first aspect of the present invention, there is provided a valve timing control device for use in an internal combustion engine. The engine comprises a sprocket driven by a timing chain in synchronization with the engine rotation and a camshaft for driving engine valves. The valve timing control device comprises a first rotating member on which the sprocket is integrally formed; a second rotating member capable of making a relative rotation to the first rotating member, the second rotating member being rotated together with the camshaft; a plurality of working fluid chambers defined between the first and second rotating members; and a working fluid actuator for charging and discharging a working fluid to and from said working fluid chambers to induce the relative rotation between the first and second rotating members, in which the sprocket and at least a base part of the first rotating member on which the sprocket is integrally formed are constructed of a porous metal member, so that the working fluid led into the working fluid chambers is allowed to penetrate into the sprocket through the base part.
According to a second aspect of the present invention, there is provided a valve timing control device for use in an internal combustion engine. The engine comprises a sprocket driven by a timing chain in synchronization with the engine rotation and a camshaft for driving engine valves. The valve timing control device controls open/close timing of the valves by varying a relative rotation between the sprocket and the camshaft. The valve timing control device comprises a first rotating member on which the sprocket is integrally formed; a second rotating member concentrically received in the first rotating member in a manner to make a relative rotation therebetween, the second rotating member being rotated together with the camshaft; a plurality of working fluid chambers defined between the first and second rotating members; and a charging/discharging means for charging and discharging a working fluid to and from the working fluid chambers to induce the relative rotation between the first and second rotating members, in which the sprocket is arranged to surround the working fluid chambers, and the sprocket and at least a base part of the first rotating member on which the sprocket is integrally formed are constructed of a porous sintered metal, so that a working fluid led into the working fluid chambers is allowed to penetrate into the sprocket through the base part.
According to a third aspect of the present invention, there is provided a valve timing control device for use in an internal combustion engine. The engine comprises a sprocket driven by a timing chain in synchronization with the engine rotation and a camshaft for driving engine valves. The valve timing control device controls open/close timing of the valves by varying a relative rotation between the sprocket and the camshaft and comprises a cylindrical housing on which the sprocket is integrally formed; a vane member concentrically received in the cylindrical housing in a manner to make a relative rotation therebetween, the vane member being rotated together with the camshaft and comprising a plurality of vanes; a plurality of working fluid chambers defined between the cylindrical housing and the vanes of the vane member; and a working fluid actuator for charging and discharging a working fluid to and from the working fluid chambers to induce the relative rotation between the cylindrical housing and the vane member, in which the sprocket is arranged to surround the working fluid chambers, and the sprocket and at. least a base part of the cylindrical housing on which the sprocket is integrally formed are constructed of a porous sintered metal, so that a working fluid led into the working fluid chambers is allowed to penetrate into the sprocket through the base part.
REFERENCES:
patent: 5875750 (1999-03-01), Iwasaki et al.
patent: 6129063 (2000-10-01), Niethammer et al.
patent: 6186103 (2001-02-01), Schafer et al.
patent: 9-324611 (1997-12-01), None
Imai Hiroaki
Maeyama Akinobu
Miyasaka Hideyuki
Foley & Lardner
Lo Weilun
Unisia Jecs Corporation
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