An oil passage switching valve suitable for a valve timing changing apparatus includes: a valve body, opening or closing an oil passage of operating oil; an urging spring, urging to position the valve body to a position corresponding to the retard position in a pause state; and a switching element, positioning the valve body to a position corresponding to the retard position when a state quantity of the operating oil is in a first range, and switching a position of the valve body in response to the state quantity (pressure or temperature) of the operating oil while resisting an urging force of the urging spring to position the valve body to a position corresponding to the advance position when the state quantity of the operating oil is in a second range greater than the first range.

The disclosure relates to a vane type camshaft adjuster for a motor vehicle drive train. The camshaft adjuster having a stator, a rotor arranged such that it can rotate relative to the stator, working chambers formed between the stator and the rotor, each working chamber being divided into two sub-chambers by a radially projecting blade of the rotor, and a reservoir connected to the sub-chambers for storing hydraulic medium. The sub-chambers can be connected to a pump or a tank according to a switch position of a control valve of the camshaft adjuster. The control valve has a switch position in which a first sub-chamber of the two sub-chambers is connected to the tank and a second sub-chamber of the two sub-chambers is blocked from the pump.

A valve timing adjustment device includes a hydraulic oil control valve. The hydraulic oil control valve includes: an outer sleeve that is shaped in a tubular form and has a projection at an outer periphery of the outer sleeve; an inner sleeve that is located on an inner side of the outer sleeve; and a spool that is located at an inside of the inner sleeve. A reference-shape portion, which serves as a reference at a time of positioning the outer sleeve relative to the inner sleeve, is formed at an outer periphery of the projection. A seat surface of the projection, which fixes a vane rotor between the seat surface of the projection and an end portion of one of a drive shaft and a driven shaft, is shaped in a rotationally symmetric form that is rotationally symmetric around a rotational axis.

A hydraulic camshaft adjuster (1), in which the locking system (7, 8) includes a first and a second control element (7, 8). In order to approach the middle position easily, the first control element (7) has a first and a second switching position, wherein in the first switching position a fluidic connection between the hydraulic pump (P) and a first of the two sub-chambers (B) and a fluidic connection between the other, second sub-chamber (A) and the tank (T) can be established, and in the second switching position a fluidic connection between the hydraulic pump (P) and the second of the two sub-chambers (A) and a fluidic connection between the other, first sub-chamber (B) and the tank (T) can be established, and the second control element (8) is free from different switching positions and has no influence on the flow of hydraulic fluid.

A check valve is made of a resilient body wound in a ring form and is located in an annular flow passage. A displacement limiter includes: a limiter main body that is located on an outer side of the check valve and is configured to limit displacement of the check valve in a diameter increasing direction of the check valve; and a limiter flow passage that communicates between one side and the other side of the limiter main body in an axial direction to enable hydraulic oil to flow between the one side and the other side of the limiter main body through the limiter flow passage.

A hydraulic oil control valve is coaxially disposed with a rotational axis of a valve timing adjustment device. The hydraulic oil control valve includes a sleeve and a spool that is slidably moved in an axial direction within the sleeve in a radial direction. The sleeve includes an inner sleeve disposed radially outside of the spool and an outer sleeve defining an axial hole extending in the axial direction. The inner sleeve is inserted into the axial hole. The outer sleeve is fixed to an end portion of one shaft when an axial force is applied to the outer sleeve in the axial direction. An inner sleeve end portion of the inner sleeve in the axial direction away from the actuator protrudes from the outer sleeve away from the actuator in the axial direction.

A hydraulic fluid control valve (HFCV) configured to recirculate an exiting hydraulic fluid from a first hydraulic actuation chamber to a second hydraulic actuation chamber is provided. The HFCV includes a spring well that combines a hydraulic fluid received from a hydraulic fluid pressure source with a recirculated hydraulic fluid from the first hydraulic actuation chamber and delivers the combination to the second hydraulic actuation chamber.

A variable camshaft timing (VCT) system includes an independent camshaft phaser, receiving input from a crankshaft of an internal combustion engine, having an output coupled to one of an inner concentric camshaft or an outer concentric camshaft; and a dependent camshaft phaser, coupled to the other of the inner concentric camshaft or the outer concentric camshaft, comprising a half-Oldham link configured to permit radial movement of the inner concentric camshaft relative to the outer concentric camshaft in one radial direction and at least one pivotable arm configured to permit radial movement of the inner concentric camshaft relative to the outer concentric camshaft in another, different radial direction.

A method for producing a cam phaser for a cam shaft of an internal combustion engine, the cam phaser including a rotor, a stator and at least one cover, the method including arranging the at least one cover at the stator wherein the at least one cover is a flat circular piece of sheet metal and the stator including internal vanes and external drive tooth is integrally provided from one piece of metal; sealing the at least one cover at the stator by applying a ground axial face of the at least one cover to a ground contact surface of the stator; and after the sealing.

A hydraulically-actuated variable camshaft timing (VCT) system comprises a spool valve including a sleeve and a spool, having a plurality of radially-outwardly extending lands, received within a sleeve; a sleeve fluid pathway, extending axially along the sleeve and formed within the sleeve, configured to receive fluid from a fluid supply; an advancing port in the sleeve in fluid communication with an advancing chamber of a hydraulically-actuated camshaft phaser; a retarding port in the sleeve in fluid communication with a retarding chamber of the hydraulically-actuated camshaft phaser; a first fluid supply port formed in the sleeve; a second fluid supply port formed in the sleeve; and an exhaust port axially positioned in the sleeve in between the first fluid supply port and the second fluid supply port or in between the advancing port and the retarding port, wherein the exhaust port is configured to selectively receive fluid from either the advancing chamber or the retarding chamber depending on an axial position of the spool relative to the sleeve.