Valve timing control apparatus for internal combustion engine

A valve timing control apparatus for an internal combustion engine, comprising:

• an intake valve timing control apparatus fixed to an intake camshaft that actuates an intake valve of the internal combustion engine;
• and
• an exhaust valve timing control apparatus fixed to an exhaust camshaft that actuates an exhaust valve of the internal combustion engine;
• wherein each of the intake valve timing control apparatus and the exhaust valve timing control apparatus comprises:
• a housing including:
• a housing body having a hollow cylindrical shape, wherein the housing body is formed integrally with a shoe at an inside periphery of the housing body, and wherein the shoe projects inwardly in a radial direction of the housing body;
• a front plate sealing a tip-side axial end of the housing body;
• a rear plate sealing a camshaft-side axial end of the housing body;
• and
• a plurality of bolts inserted through bolt holes formed in the shoe of the housing body, the front plate, and the rear plate, for fixing the housing body, the front plate, and the rear plate together;
• a vane rotor including:
• a rotor rotatably mounted in the housing, and fixed to a respective one of the intake camshaft and the exhaust camshaft;
• and
• a vane formed integrally with the rotor, projecting outwardly in a radial direction of the rotor, wherein the vane and the shoe define an advance chamber and a retard chamber between the vane rotor and housing, and wherein the advance chamber and the retard chamber are adapted to supply and drainage of fluid;
• and
• a lock member arranged to selectively lock and release the vane rotor with respect to the housing according to a state of operation of the internal combustion engine;
• wherein in the intake valve timing control apparatus, the lock member is arranged to lock the vane rotor with respect to the housing under a condition that the vane rotor is in a most retarded position;
• wherein in the exhaust valve timing control apparatus, the lock member is arranged to lock the vane rotor with respect to the housing under a condition that the vane rotor is in a most advanced position;
• wherein the exhaust valve timing control apparatus further comprises a biasing member arranged to bias the vane rotor with respect to the housing in a direction toward the most advanced position;
• wherein the housing body of the intake valve timing control apparatus and the housing body of the exhaust valve timing control apparatus are mirror images of each other, both of which are formed from an identical base workpiece, wherein the base workpiece of the housing body is formed by extruding an aluminum-based metal material, and cutting an extruded workpiece;
• and
• wherein the vane rotor of the intake valve timing control apparatus and the vane rotor of the exhaust valve timing control apparatus are mirror images of each other, both of which are formed from an identical base workpiece, wherein the base workpiece of the vane rotor is formed by extruding an aluminum-based metal material, and cutting an extruded workpiece.

A valve timing control apparatus for an internal combustion engine, comprising:

• an intake valve timing control apparatus fixed to an intake camshaft that actuates an intake valve of the internal combustion engine;
• and
• an exhaust valve timing control apparatus fixed to an exhaust camshaft that actuates an exhaust valve of the internal combustion engine;
• wherein each of the intake valve timing control apparatus and the exhaust valve timing control apparatus comprises:
• a housing including:
• a housing body having a hollow cylindrical shape, wherein the housing body is formed integrally with a shoe at an inside periphery of the housing body, and wherein the shoe projects inwardly in a radial direction of the housing body;
• a front plate sealing a first axial end of the housing body;
• a rear plate sealing a second axial end of the housing body;
• and
• a plurality of bolts inserted through bolt holes formed in the shoe of the housing body, the front plate, and the rear plate, for fixing the housing body, the front plate, and the rear plate together;
• a vane rotor including:
• a rotor rotatably mounted in the housing, and fixed to a respective one of the intake camshaft and the exhaust camshaft;
• and
• a vane formed integrally with the rotor, projecting outwardly in a radial direction of the rotor, wherein the vane and the shoe define an advance chamber and a retard chamber between the vane rotor and housing, and wherein the advance chamber and the retard chamber are adapted to supply and drainage of fluid;
• and
• a lock member arranged to selectively lock and release the vane rotor with respect to the housing according to a state of operation of the internal combustion engine;
• wherein in the intake valve timing control apparatus, the lock member is arranged to lock the vane rotor with respect to the housing under a condition that the vane rotor is in a most retarded position;
• wherein in the exhaust valve timing control apparatus, the lock member is arranged to lock the vane rotor with respect to the housing under a condition that the vane rotor is in a most advanced position;
• wherein in the intake valve timing control apparatus, a contact pressure between contact surfaces of the vane rotor and the housing which is caused by rotation of the vane rotor with respect to the housing in a first rotational direction toward the most retarded position, is smaller than a contact pressure between contact surfaces of the vane rotor and the housing which is caused by rotation of the vane rotor with respect to the housing in a second rotational direction opposite to the first rotational direction;
• wherein in the exhaust valve timing control apparatus, a contact pressure between contact surfaces of the vane rotor and the housing which is caused by rotation of the vane rotor with respect to the housing in a first rotational direction toward the most advanced position, is smaller than a contact pressure between contact surfaces of the vane rotor and the housing which is caused by rotation of the vane rotor with respect to the housing in a second rotational direction opposite to the first rotational direction;
• and
• wherein in each of the intake valve timing control apparatus and the exhaust valve timing control apparatus, each of the housing body and the vane rotor is formed by extruding an aluminum-based metal.