Valve timing control system of internal combustion engine

Claim 2

A valve timing control system of an internal combustion engine, comprising: a generally cylindrical rotatable member movably connected to an end section of a camshaft, said rotatable member being drivably connected with a crankshaft of the engine; an arm fixedly connected to the end section of said camshaft and extending generally diametrically of said rotatable member; first and second plungers slidably movably disposed in and extending along an axial direction of said rotatable member, each of said first and second plungers defining a hydraulic pressure chamber and being projectable toward said arm upon supply of a hydraulic pressure to said hydraulic pressure chamber, each of said first and second plungers having a thrusting portion, said thrusting portion having an inclined surface adapted to cause said arm to circumferentially rotationally move relative to said rotatable member upon projection of said plunger, the hydraulic pressure being supplied to said hydraulic pressure chamber through a check valve; and change-over means for changing over the supply of the hydraulic pressure to said pressure chambers of said first and second plungers in accordance with an engine operating condition.

Claim 3

A valve timing control system of an internal combustion engine, comprising: a generally cylindrical rotatable member coaxially and movably connected to one end section of a camshaft, said rotatable member being drivably connected to a crankshaft of the engine; an arm fixedly connected to the one end section of said camshaft and extending generally diametrically of said rotatable member, said arm including first and second arm sections which extend generally radially outwardly and generally in opposite directions to each other; first and second plungers slidably movably disposed and extending along an axial direction of said rotatable member, each of said first and second plunger being projectable toward said arm and having a thrusting portion, said thrusting portion having an inclined surface adapted to contact with and push each of said first and second arm sections so that said arm makes its circumferentially rotational movement around an axis of the camshaft relative to said rotatable member upon projection of said plunger, said first and second plungers being located to cause said arm to make the rotational movement in opposite directions, respectively, upon projection of said first and second plungers; first and second hydraulic pressure chambers to be supplied with a hydraulic pressure, at least a part of said first hydraulic chamber being defined by said first plunger so that said first plunger projects toward said first arm section of said arm upon supply of said hydraulic pressure to said first hydraulic pressure chamber, at least a part of said second hydraulic pressure chamber being defined by said second plungers so that said second plunger projects toward said second arm section of said arm upon supply of the hydraulic pressure to said second hydraulic pressure chamber; first and second check valves through which the hydraulic pressure is supplied to said respective first and second hydraulic pressure chambers; and change-over means for changing over the supply of the hydraulic pressure to said first and second hydraulic pressure chambers in accordance with an engine operating condition.

Claim 4

A valve timing control system of an internal combustion engine, comprising: a generally cylindrical rotatable member coaxially and movably connected to one end section of a camshaft, said rotatable member being drivably connected to a crankshaft of the engine; an arm fixedly connected to the one end section of said camshaft and extending generally diametrically of said rotatable member, said arm including first and second arm sections which extend generally radially outwardly and generally in opposite directions to each other; first and second plungers slidably movably disposed and extending along an axial direction of said rotatable member, each of said first and second plunger being projectable toward said arm and having a thrusting portion, said thrusting portion having an inclined surface adapted to contact with and push each of said first and second arm sections so that said arm makes its circumferentially rotational movement around an axis of the camshaft relative to said rotatable member upon projection of said plunger, said first and second plungers being located to cause said arm to make the rotational movement in opposite directions, respectively, upon projection of said first and second plungers; first and second hydraulic pressure chambers to be supplied with a hydraulic pressure, at least a part of said first hydraulic chamber being defined by said first plunger so that said first plunger projects toward said first arm section of said arm upon supply of said hydraulic pressure to said first hydraulic pressure chamber, at least a part of said second hydraulic pressure chamber being defined by said second plungers so that said second plunger projects toward said second arm section of said arm upon supply of the hydraulic pressure to said second hydraulic pressure chamber; first and second check valves through which the hydraulic pressure is supplied to said respective first and second hydraulic pressure chambers; and change-over means for changing over the supply of the hydraulic pressure to said first and second hydraulic pressure chambers in accordance with an engine operating condition.

Claim 5

A valve timing control system as claimed in claim 2, wherein said change-over means includes means for selectively supplying the hydraulic pressure to one of said first and second hydraulic pressure chambers in accordance with the engine operating condition.

Claim 6

A valve timing control system as claimed in claim 2, further comprising a generally cylindrical sleeve coaxially and fixedly connected to the end section of the camshaft, said rotatable member being slidably movably mounted on said sleeve, said arm being fixedly secured to said sleeve.

Claim 7

A valve timing control system as claimed in claim 4, wherein said rotatable member is formed with first and second cylindrical bores extending along the axial direction of said rotatable member, said first and second plungers being slidably movably disposed respectively in said first and second cylindrical bores, said first and second hydraulic pressure chambers being defined respectively in said first and second cylindrical bores.

Claim 8

A valve timing control system as claimed in claim 5, wherein said first and second plungers are respectively formed therein with hydraulic fluid reservoir chambers which are respectively connectable through said first and second check valves with said first and second hydraulic pressure chambers, said first and second reservoir chambers being connected with a hydraulic pressure source.

Claim 9

A valve timing control system as claimed in claim 2, wherein said change-over means includes first and second pressure releasing means respectively for allowing the hydraulic pressures in said first and second hydraulic pressure chambers to release upon being actuated, and control means for selectively actuating said first and second pressure releasing means in accordance with the engine operating condition.