Variable valve timing apparatus

An apparatus for controlling a valve timing in an internal combustion engine, having an engine block, a crankshaft mounted to the engine block, a camshaft mounted to the engine block, and a power receiving member rotatably mounted on the camshaft for receiving a rotational movement from the crankshaft, said engine including an oil supply passageway in the engine block for a lubrication of various parts therein, said apparatus comprising:

• a housing connected to the engine block;
• a first sleeve member fixedly connected to one end of the camshaft, the first sleeve member defining, at a cylindrical surface thereof, a helical spline;
• a second sleeve member fixedly connected to the power receiving member;
• a timing piston movable along the axis of the camshaft, the timing piston having a first helical spline portion engaging with the first sleeve member and a second spline portion engaging the second sleeve in such a manner that the axial movement of the timing piston causes a mutual angular positioning between the camshaft and the power receiving member to be obtained;
• rotary drive means for generating a rotating movement;
• a feed mechanism having a rotating part rotatable with respect to the housing and connected to said rotary drive means and a linearly moving part moved with respect to the housing along the axis of the camshaft upon the rotation of the rotating part;
• means for connecting the linearly moving part to the timing piston for a transmission of the axial movement of the feed mechanism to the timing piston;
• said oil supply passageway being opened to a space formed between the housing and an engine block for lubricating the parts therein, including the feed mechanism, and;
• means for defining an oil return passageway constructed such that the oil supplied to the feed mechanism is exhausted and does not remain therein when the engine is stopped.

An apparatus for controlling a valve timing in an internal combustion engine, having an engine block, a crankshaft mounted to the engine block, a camshaft mounted to the engine block, and a power receiving member rotatably mounted on the camshaft for receiving a rotational movement of the crankshaft, said apparatus comprising:

• a housing;
• a first sleeve member fixedly connected to one end of the camshaft, the first sleeve member defining, at a cylindrical surface thereof, a helical spline;
• a second sleeve member fixedly connected to the power receiving member;
• a timing piston movable along the axis of the camshaft, the timing piston having a first helical spline portion engaging with the first sleeve member and a second spline portion engaging the second sleeve in such a manner that the axial movement of the timing piston causes a mutual angular positioning between the camshaft and the power receiving member to be obtained;
• means for fixing the housing to the engine block;
• rotary drive means for generating a rotating movement;
• a feed mechanism having a rotating part rotatable with the housing and connected to said rotary drive means and a linearly moving part which is moved with respect to the housing along the axis of the camshaft upon the rotation of the rotating part, and;
• means for connecting the linearly moving part with the timing piston so that the axial movement of the feed mechanism is transmitted to the timing piston during a rotation thereof, and a limited radial, relative movement is allowed between the linearly moving part and the timing piston;
• said housing together with the timing piston, the feed mechanism and the connecting means constructing a sub-assembly connected to the engine block by said fixing means.