A variable camshaft timing system including a first camshaft phaser having an input that is configured to receive rotational force from a crankshaft and an output that is configured to link with a first camshaft of a concentric camshaft assembly to change the angular position of the first camshaft relative to a crankshaft; and a second camshaft phaser having an output that is configured to link with a second camshaft of the concentric camshaft assembly to change the angular position of the second camshaft relative to the crankshaft, wherein the first camshaft is concentrically positioned to the first camshaft and the first camshaft phaser is mechanically linked to the second camshaft phaser to communicate rotational force from the crankshaft to the second camshaft phaser through the first camshaft phaser and the mechanical link.

A cam phasing system is provided. In some non-limiting examples, the cam phasing system includes a planetary actuator having a first sun gear, a first set of planet gears meshed to and arranged circumferentially around the first sun gear, a first ring gear meshed with the first set of planet gears, and a second sun gear. The second sun gear is rotationally fixed. The planetary actuator further includes a second set of planet gears meshed to and arranged circumferentially around the second sun gear, a second ring gear meshed with the second set of planet gears, and an input shaft rotationally coupled to the first sun gear for rotation therewith. Rotation of the input shaft rotates the first ring gear relative to the second ring gear.

Various embodiments include a method for actuating a camshaft adjuster of an internal combustion engine, in which a current is generated in an electric motor of the camshaft adjuster comprising: measuring an instantaneous strength of the current; calculating a mean value of the measured strength of the current over a predefined elapsed time; measuring a temperature of the camshaft adjuster; comparing the mean value of the measured strength of the current to a threshold value obtained from a characteristic diagram stored in a memory based on the measured temperature and the predefined elapsed time; and reducing the current if the calculated mean value of the strength of the current is higher than the threshold value.

An engine variable camshaft timing (VCT) phaser assembly is equipped in an internal combustion engine (ICE) to adjust the rotation of the engine's camshaft relative to the engine's crankshaft. The adjustments advance and retard the opening and closing movements of the engine's intake and exhaust valves. An electric motor and a planetary gear set work together amid use of the VCT phaser assembly. The planetary gear set can include two or more ring gears, planet gears, and a sun gear. A backlash condition sometimes experienced in previous VCTs is minimized in the VCT phaser assembly by one or more springs that urge the planet gears into engagement with the ring gears.

A bearing portion of a planetary rotatable body for providing bearing support in a thrust direction is defined as a planetary thrust bearing portion. A driving-side rotatable body or a driven-side rotatable body, which is configured to contact the planetary thrust bearing portion in the thrust direction, is defined as a specific rotatable body. A bearing portion of the specific rotatable body for providing bearing support in the thrust direction is defined as a specific thrust bearing portion. In a parallel state where the specific thrust bearing portion and the planetary thrust bearing portion are parallel to each other, the specific thrust bearing portion and the planetary thrust bearing portion contact with each other only on one of an eccentric side and a counter-eccentric side of the planetary rotatable body while the counter-eccentric side is opposite to the eccentric side.

A differential includes a drive rotating body rotatable about a rotation axis, a planetary rotating body that is rotatable and is revolvable about the rotation axis, and a driven rotating body rotatable about the rotation axis. The planetary rotating body is made to mesh with each of the drive rotating body and the driven rotating body, so that a first speed reducer is constituted between the planetary rotating body and the drive rotating body and so that a second speed reducer is constituted between the planetary rotating body and the driven rotating body. The planetary rotating body is driven by an electric motor, and the drive rotating body is driven by a driving force from an engine. The intake camshaft is provided on the driven rotating body, and the exhaust camshaft is provided on the drive rotating body.

A differential device (5) of an electric actuator (1) includes a driving rotary body (2), a driven rotary body (3), and a planetary rotary body (52). A first speed reducer (5a) is formed between the planetary rotary body (52) and the driving rotary body (2). A second speed reducer (5b) is formed between the planetary rotary body (52) and the driven rotary body (3). The electric actuator (1) includes a first bearing (53) configured to support the planetary rotary body (52) on an inner side of a rotor (42) of an electric motor (4), and a second bearing (54) configured to support the planetary rotary body (52) at a position shifted in an axial direction so as to be prevented from overlapping the rotor (42). The second bearing (54) is formed of a deep-groove ball bearing.

A valve opening and closing timing control device includes a driving-side rotating body, a driven-side rotating body, a stopper configured to determine a mechanical limit of a displacement region of a relative rotation phase, a phase control mechanism configured to change the relative rotation phase, and a control unit configured to control the electric motor so as to displace the actual phase detected by a phase sensor. A limit phase at which the stopper reaches an abutting state is set in advance when rotation of the electric motor is stopped while the internal combustion engine operates. Upon executing stop control of stopping the internal combustion engine, except when the actual phase is already the limit phase, the control unit executes braking control of limiting the rotation of the electric motor by controlling an electric current to be supplied to the electric motor.

An object of the present invention is to obtain a controller device for a variable valve timing apparatus capable of controlling a phase to an arbitrary fixed valve timing from immediately before an internal combustion engine stops until after the internal combustion engine has stopped. The controller device for the variable valve timing apparatus according to the present invention performs, during engine stop processing of the internal combustion engine, normal control of changing the relative rotational phase of a camshaft to a most advanced position or a most retarded position when the rotational speed of a crankshaft is equal to or more than a first threshold, and low-speed control of fixing a current or a voltage supplied to the motor to be constant to maintain the relative rotational phase of the camshaft at the most advanced position or the most retarded position in a period from when the rotational speed of the crankshaft is lower than the first threshold until the rotational speed becomes zero.

An Oldham coupling includes an engagement arm. At least either a driving-side rotor or an input gear has an engagement portion engaged with the engagement arm and is connected to the Oldham coupling. The engagement arm has a pair of arm flat surface portions perpendicular to a rotational direction of the driving-side rotor. The engagement portion has a pair of engagement flat surface portions that the arm flat surface portions face in a sliding contact manner. Each arm flat surface portion is, within a range where the arm flat surface portion slides against a facing engagement flat surface portion, always in contact with an overlapping portion of the engagement flat surface portion with the arm flat surface portion when viewed from a direction perpendicular to a sliding direction of the Oldham coupling and in which the arm flat surface portion and the engagement flat surface portion overlap each other.