Internal-combustion engines – Poppet valve operating mechanism – With means for varying timing
Reexamination Certificate
2000-09-14
2001-11-20
Lo, Weilun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
With means for varying timing
C074S56800M, C464S002000
Reexamination Certificate
active
06318319
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a valve timing control device for controlling timings of opening and closing an engine valve during the engine operation.
There is known a valve timing control device of the type, which is disposed between a rotary element rotatively driven by a crank shaft of an internal combustion engine and a cam shaft for actuating an engine valve, i.e., intake or exhaust valve. The valve timing control device is adapted to vary timings of opening and closing the engine valve by rotating the cam shaft relative to the rotary element.
Japanese Patent Application First Publication No. 8-121123 discloses a valve timing control device including a housing rotating with a rotary element driven by a crank shaft of an internal combustion engine, a rotor rotating with a cam shaft and vanes extending from the rotor. The vanes define a plurality of hydraulic fluid chambers within the housing. The device also includes a mechanism for supplying a hydraulic fluid to the chambers and discharging the hydraulic fluid therefrom. The housing and the rotor are relatively rotated by a difference of the fluid pressure within the chambers. Fluid communication between the mechanism and the chambers is established via fluid passages formed in the rotor and fluid passages formed in the cam shaft or a rotating support fixed to the cam shaft and the rotor. The rotor has an axial end face mating with an axial end face of the cam shaft or an axial end face of the rotating support. The fluid passages of the rotor and the fluid passages of the cam shaft or the rotating support are open to the corresponding axial end faces, respectively, and in axial alignment. Fluid communication between fluid paths of the mechanism and the fluid passages of the cam shaft or rotating support is established between an outer circumferential surface of the cam shaft or rotating support and an inner circumferential surface of a journal supporting the cam shaft or the rotating support.
SUMMARY OF THE INVENTION
In the conventionally proposed technique described above, it is required to increase an axial dimension of the cam shaft to assure the fluid communication between the outer circumferential surface of the cam shaft and the inner circumferential surface of the journal. This will cause an increase in dimension of the internal combustion engine as a whole, resulting in a great modification of design of the existing internal combustion engine to which the conventionally proposed valve timing control device is applied. On the other hand, it is required to increase a size of the valve timing control device to assure the fluid communication between the outer circumferential surface of the rotating support and the inner circumferential surface of the journal.
It is an object of the present invention to provide a valve timing control device reduced in size and applicable to the existing internal combustion engine.
According to one aspect of the present invention, there is provided a valve timing control device for varying an opening and closing timing of an engine valve in an internal combustion engine, the device being disposed between a rotary element synchronously rotating with the engine and a camshaft actuating the engine valve, the device comprising:
a housing adapted to rotate with one of the rotary element and the camshaft;
a vane rotor disposed within said housing, said vane rotor having an axial bore having an open end and pressure chamber-side fluid passages open to said axial bore, said vane rotor being adapted to rotate with the other of the rotary element and the camshaft;
a vane radially extending from said vane rotor and defining within said housing at least a pair of fluid pressure chambers communicating with said pressure chamber-side fluid passages, respectively, said fluid pressure chambers being circumferentially disposed within said housing;
a fluid control mechanism for supplying a hydraulic fluid to said fluid pressure chambers and discharging the hydraulic fluid therefrom; and
a shaft received in said axial bore of said vane rotor through said open end, said shaft being formed with pressure source-side fluid passages communicating with said pressure chamber-side fluid passages and said fluid control mechanism.
According to a further aspect of the present invention, there is provided a valve timing control device, comprising:
a housing;
a vane rotor with at least one vane and rotatable relative to said housing, said vane rotor having an axial bore and fluid passages open to the axial bore;
at least a pair of fluid pressure chambers defined by the housing and the vane rotor with the vane, said fluid passages being open to the fluid pressure chambers, respectively;
a lock mechanism for restricting relative rotation of the housing and the rotor, said lock mechanism comprising a fluid pressure chamber fluidly communicated with one of the pair of fluid pressure chambers;
a fluid control mechanism for supplying a hydraulic fluid to the fluid pressure chambers and discharging the hydraulic fluid therefrom;
a shaft received in the axial bore of the rotor;
first communication fluid path communicating with one of the pair of fluid pressure chambers and the fluid control mechanism via the corresponding fluid passage, said first communication fluid path being formed in the shaft; and
second communication fluid path communicating with the other of the pair of fluid pressure chambers and the fluid control mechanism via the corresponding fluid passage, said second communication fluid path being formed in the shaft.
REFERENCES:
patent: 5205249 (1993-04-01), Markley et al.
patent: 5450825 (1995-09-01), Geyer et al.
patent: 5666914 (1997-09-01), Ushida et al.
patent: 5988126 (1999-11-01), Strauss et al.
patent: 08-121123 (1996-05-01), None
Ichinosawa Yoshinori
Miyasaka Hideyuki
Nakura Naotaka
Foley & Lardner
Lo Weilun
Unisia Jecs Corporation
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