Valve timing control system for internal combustion engine

An internal combustion engine, comprising:

• a crankshaft;
• a camshaft;
• a housing comprising a main body having a concave space and a cover member mounted to the main body to close the space, the cover member being formed with a through hole;
• a phase adjusting mechanism accommodated in the housing, the phase adjusting mechanism hydraulically changing a rotation phase of the crankshaft and the camshaft;
• a supply and discharge rod arranged through the through hole of the cover member, the supply and discharge rod being connected to the phase adjusting mechanism, the supply and discharge rod failing to be rotatable;
• a seal ring externally engaged with the supply and discharge rod, the seal ring hermetically sealing a clearance between the supply and discharge rod and the phase adjusting mechanism;
• and
• a protrusion formed with the cover member, the protrusion having the through hole formed therethrough, the protrusion protruding from an inner periphery of the through hole in an axial direction of the system, the protrusion having inner and outer peripheries extending to increase a diameter of the through hole toward the outside of the housing.

A system for controlling a valve timing in an internal combustion engine, comprising:

• a housing comprising a main body having a concave space and a cover member mounted to the main body to close the space, the cover member being formed with a through hole;
• a phase adjusting mechanism accommodated in the housing, the phase adjusting mechanism hydraulically changing a rotation phase of a crankshaft and a camshaft;
• a supply and discharge rod arranged through the through hole of the cover member, the supply and discharge rod being connected to the phase adjusting mechanism, the supply and discharge rod failing to be rotatable;
• a seal ring externally engaged with the supply and discharge rod, the seal ring hermetically sealing a clearance between the supply and discharge rod and the phase adjusting mechanism;
• a taper surface formed on a periphery of the through hole of the cover member, the taper surface increasing a diameter of the through hole toward the outside of the housing, the taper surface being curved as viewed in a section along the axial direction of the system;
• and
• a protrusion formed with the cover member in a radially inside area thereof, the protrusion protruding in an axial direction of the system, the through hole being formed at the protrusion.

A method of manufacturing a cover member for use in a system for controlling a valve timing in an internal combustion engine, the method comprising:

• preparing a disk-like plate material having a hole previously formed in a position corresponding to the through hole of the cover member;
• applying a first press forming to an edge of the hole of the plate material using a first cylindrical punch, the first press forming expanding the edge of the hole axially cylindrically;
• and
• applying a second press forming to the plate material using a second taper punch, the second press forming extending like a taper a cylindrical wall of the plate material in its entirety in conformity with the second punch by inserting the second punch into an end of the cylindrical wall,
• whereby a taper surface is formed on a periphery of the through hole of the cover member, the taper surface increasing a diameter of the through hole toward the outside of the housing,
• the protrusion is formed with the cover member in a radially inside area thereof, the protrusion protruding in an axial direction of the system, and
• the through hole is formed at the protrusion.