A camshaft phaser, including: a stator including radially inwardly extending protrusions with radially outermost ends; a rotor including radially outwardly extending protrusions radially outermost ends; chambers at least partially bounded by a inwardly extending protrusion and an outwardly extending protrusion; first seals disposed in the radially innermost ends and facing the rotor; second seals disposed in the radially outermost ends and facing the stator; first and second wedge plates radially disposed between the rotor and the stator; and a displacement assembly arranged to for an advance mode, displace the first wedge plate to enable rotation of the rotor, with respect to the stator, in the first circumferential direction and for a retard mode, displace the second wedge plate to enable rotation of the rotor, with respect to the stator, in a second circumferential direction opposite the first circumferential direction.

Methods and systems are described for an engine with a cam torque actuated variable cam timing phaser. Phaser positioning control is improved by reducing inaccuracies resulting from inadvertent spool valve and/or phaser movement when the spool valve is commanded between regions. In addition, improved spool valve mapping is used to render phaser commands more consistent and robust.

An engine variable camshaft timing phaser (10) includes a sprocket (12) and a planetary gear assembly (14). The sprocket (12) receives rotational drive input from an engine crankshaft. The planetary gear assembly (14) includes two or more ring gears (26, 28), multiple planet gears (24), a sun gear (22), and a wrap spring (76). One of the ring gears (26, 28) receives rotational drive input from the sprocket (12) and one of the ring gears (26, 28) transmits rotational drive output to an engine camshaft. The sun gear (22) engages with the planet gears (24). The wrap spring (76) experiences expansion and contraction exertions to permit advancing and retarding engine valve opening and closing, and to prevent advancing and retarding engine valve opening and closing.

A camshaft phaser includes an input member an output member defining an advance chamber and a retard chamber; a valve spool having a valve spool bore; a first recirculation check valve and a second recirculation check valve disposed within the valve spool bore; and a biasing member which biases the first recirculation check valve and the second recirculation check valve away from each other. The first recirculation check valve allows oil to pass from the advance chamber to the retard chamber and prevents oil from passing from the retard chamber to the advance chamber when the valve spool is in a retard position. The second recirculation check valve allows oil to pass from the retard chamber to the advance chamber and prevents oil from passing from the advance chamber to the retard chamber when the valve spool is in an advance position.

A drain port of a hydraulic oil controller is connected to an oil discharge portion. Each of partitions partitions between a corresponding one of drain oil passages and a corresponding one of a retard supply oil passage and an advance supply oil passage. Each of the drain oil passages connects between the oil discharge portion and a corresponding one of a retard chamber and an advance chamber. A recycle oil passage connects between: a portion of each drain oil passage located between the corresponding partition and the drain port; and the retard supply oil passage or the advance supply oil passage. A drain flow restrictor is formed in the portion of each drain oil passage located between the corresponding partition and the drain port. A passage cross-sectional area of the drain flow restrictor is smaller than a smallest passage cross-sectional area of the recycle oil passage and is constant.

A camshaft may include a shaft as well as a sliding element that is disposed on the shaft such that the sliding element is axially displaceable along a shaft axis. The shaft may comprise an external tooth for transmitting torque between the shaft and the sliding element. The external tooth may engage a mating tooth geometry formed in a passage of the sliding element. The sliding element on its axial end faces may comprise bearing collars that with the shaft form radial supporting bearings of the sliding element on the shaft. Further, the shaft may comprise cylindrical bearing portions for forming the radial supporting bearings, wherein the bearing portions can be configured with a diameter that is smaller than a diameter circumscribed by tips of the mating tooth geometry that protrude into the passage of the sliding element.

A camshaft adjusting device including a vane cell adjuster with a stator which can be connected to a crankshaft of an internal combustion engine and with a rotor which is rotatably mounted in the stator and can be connected to a camshaft. The camshaft adjusting device also includes a central locking device for locking the rotor in a central locking position relative to the stator. In one or more of the vanes together: at least two pressure medium lines are provided, each of which fluidically connects two working chambers with different working directions to each other. Non-return valves with different working directions are provided in each pressure medium line, each non-return valve allowing a flow of the pressure medium between the working chambers in one direction and preventing the flow in the respective other direction depending on the rotational direction of the rotor relative to the stator. A first switchable valve device is provided in the respective other vanes which are not provided with non-return valves, the valve device allowing a flow of the pressure medium between the working chambers with different working directions in one switch position.

A hydraulic camshaft adjuster having: a stator with a radially inwardly opening working chamber a rotor arranged radially within the stator, wherein the rotor receives a vane dividing the working chamber into two part chambers, and rotatable relative to the stator about a rotational axis dependent on a hydraulic pressure set in the part chambers . A central valve controls the hydraulic pressure and is configured for selectively connecting individual hydraulic lines which open into the part chambers among one another and/or to a supply line.A check valve device is integrated per part chamber into a first hydraulic line configured in the vane, which check valve device is arranged to act in a permanently closing manner in a first hydraulic flow direction from the central valve into the respective part chamber and can be opened dependent on the hydraulic pressure in a second hydraulic flow direction which is opposed to the first hydraulic flow direction.

A hydraulic valve, in particular for a phaser of a cam shaft, the hydraulic valve including a bushing including a piston that is displaceable in a bore hole along a longitudinal direction; a supply connection configured to supply a hydraulic fluid; at least a first operating connection and a second operating connection; and at least one tank drain configured to drain the hydraulic fluid, wherein the first operating connection and the second operating connection are alternatively connectable with each other and/or with the supply connection and/or with the at least one tank drain through at least one check valve by displacing the piston.

A piston for a hydraulic valve of a rotation phaser, wherein the piston is configured hollow cylindrical, wherein the piston is axially movable in a central opening extending along a first longitudinal axis of a housing of the hydraulic valve, wherein operating connections of the housing are opened and closed according to a position of the piston, wherein the piston includes check valves which prevent an unintentional outflow of a hydraulic fluid flowing through the piston from an inner cavity of the piston in flow through openings of the piston associated with the operating connections, wherein the piston is configured with check valves in its inner cavity that open towards its interior cavity, wherein the check valves are fixated by a spacer element that is arranged between the two check valves. The invention also relates to a hydraulic valve for a rotation phaser of a cam shaft.