Abstract: In a variable valve system for an internal combustion engine and its driving mechanism, the variable valve system comprises: a variable mechanism that revolves a control axle to change an operation characteristic of an engine valve; a projection section projected at an outer peripheral predetermined position in an axial direction of the control axle and on a tip of which a fixture section is formed; a fixture member fixed in a grasped state for the projection member via an engagement member engaged on the fixture section; a driving mechanism configured to provide a rotating force for the control axle via the fixture member; and control means (a control section) for controlling the driving mechanism in accordance with a driving state of the engine.

Abstract: In a variable valve system for an internal combustion engine and its driving mechanism, the variable valve system comprises: a variable mechanism that revolves a control axle to change an operation characteristic of an engine valve; a projection section projected at an outer peripheral predetermined position in an axial direction of the control axle and on a tip of which a fixture section is formed; a fixture member fixed in a grasped state for the projection member via an engagement member engaged on the fixture section; a driving mechanism configured to provide a rotating force for the control axle via the fixture member; and control means (a control section) for controlling the driving mechanism in accordance with a driving state of the engine.

Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: A valve timing control system has a tubular housing; a cam shaft having an external periphery formed with a drive cam; a phase variation mechanism disposed in the tubular housing, and varying a rotational phase of the sprocket portion relative to the cam shaft in accordance with oil pressure supplied to the phase variation mechanism; and an oil pressure control measures for controlling the oil pressure supplied to the phase variation mechanism. The tubular housing has a housing body having a density, and a sprocket portion for receiving a drive force transmitted from a crank shaft of an engine by way of a chain. The sprocket portion is disposed integrally to the tubular housing, and has a density higher than the density of the housing body. The tubular housing is so mounted to the cam shaft as to make a rotation relative to the cam shaft when so required.

Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: An oil pressure control apparatus for an internal combustion engine that has a source of hydraulic pressure and a hydraulic actuator which is actuated by hydraulic pressure provided via a fluid passage which is in communication with the source of hydraulic pressure. A control valve is disposed in the fluid passage for controlling the hydraulic pressure introduced to the actuator. A damper, which is disposed in a fluid communication between the hydraulic actuator and the control valve, is operative to attenuate the force of a pulsing stream of a working fluid in the fluid passage.

Abstract: A valve timing control system has a tubular housing; a cam shaft having an external periphery formed with a drive cam; a phase variation mechanism disposed in the tubular housing, and varying a rotational phase of the sprocket portion relative to the cam shaft in accordance with oil pressure supplied to the phase variation mechanism; and an oil pressure control measures for controlling the oil pressure supplied to the phase variation mechanism. The tubular housing has a housing body having a density, and a sprocket portion for receiving a drive force transmitted from a crank shaft of an engine by way of a chain. The sprocket portion is disposed integrally to the tubular housing, and has a density higher than the density of the housing body. The tubular housing is so mounted to the cam shaft as to make a rotation relative to the cam shaft when so required.

Abstract: A valve timing control system has a tubular housing; a cam shaft having an external periphery formed with a drive cam; a phase variation mechanism disposed in the tubular housing, and varying a rotational phase of the sprocket portion relative to the cam shaft in accordance with oil pressure supplied to the phase variation mechanism; and an oil pressure control measures for controlling the oil pressure supplied to the phase variation mechanism. The tubular housing has a housing body having a density, and a sprocket portion for receiving a drive force transmitted from a crank shaft of an engine by way of a chain. The sprocket portion is disposed integrally to the tubular housing, and has a density higher than the density of the housing body. The tubular housing is so mounted to the cam shaft as to make a rotation relative to the cam shaft when so required.

Abstract: An oil pressure control apparatus which includes a source of hydraulic pressure introducing the hydraulic pressure to a hydraulic actuator which is actuated by hydraulic pressure, a fluid passage which is connected between the source of hydraulic pressure and the hydraulic actuator for introducing and discharging hydraulic pressure from the source of hydraulic pressure to the actuator, a control valve which is disposed in the fluid passages for controlling the hydraulic pressure and a filter is disposed in a position that is between the actuator and the control valve. Thereby, the control valve is capable to be operated smoothly.

Abstract: A valve timing control system has a tubular housing; a cam shaft having an external periphery formed with a drive cam; a phase variation mechanism disposed in the tubular housing, and varying a rotational phase of the sprocket portion relative to the cam shaft in accordance with oil pressure supplied to the phase variation mechanism; and an oil pressure control measures for controlling the oil pressure supplied to the phase variation mechanism. The tubular housing has a housing body having a density, and a sprocket portion for receiving a drive force transmitted from a crank shaft of an engine by way of a chain. The sprocket portion is disposed integrally to the tubular housing, and has a density higher than the density of the housing body. The tubular housing is so mounted to the cam shaft as to make a rotation relative to the cam shaft when so required.

Abstract: An oil pressure control apparatus for an internal combustion engine that has a source of hydraulic pressure and a hydraulic actuator which is actuated by hydraulic pressure provided via a fluid passage which is in communication with the source of hydraulic pressure. A control valve is disposed in the fluid passage for controlling the hydraulic pressure introduced to the actuator. A damper, which is disposed in a fluid communication between the hydraulic actuator and the control valve, is operative to attenuate the force of a pulsing stream of a working fluid in the fluid passage.

Abstract: An internal combustion engine has a sprocket driven by a timing chain in synchronization with the engine rotation and a camshaft for driving intake or exhaust valves. A valve timing control device of the engine 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 and 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. 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.