Abstract: A phase change coupling is disclosed for allowing the angular position of a drive member 10 of a camshaft 12 to be varied in relation to the camshaft. The coupling is additionally provided with a locking mechanism for preventing rotation of the drive member relative to the camshaft in only one direction during cranking of the engine, so that, during cranking of the engine, the drive member 10 is rotated in only one sense relative to the camshaft by the camshaft torque reversals until it reaches a predetermined start-up angular position.

Abstract: In a phase change mechanism in which the phase of a driven member (10) relative to a drive member (12) is adjusted by axial displacement of an actuating rod (30) connected to the piston (50) of a hydraulic jack rotatable with the drive and driven members, the cylinder (52) of the hydraulic jack has a double-skinned wall, and the gap (54) between the two skins of the cylinder wall serves as a passage for supplying oil to and from one of the working chambers of the hydraulic jack.

Abstract: A variable phase mechanism comprises a hollow shaft 16, first 10 and second 14 members rotatable about the hollow shaft 16 and two yokes 18, 20 surrounding the hollow shaft 16, one yoke 18 coupling the hollow shaft 16 for rotation with first member 10 and the other yoke 20 coupling the second member 14 for rotation with the first member 10. An actuating rod 32 is slidably received in the hollow shaft 16, and has cam surfaces 36, 38 that on the first yoke 18 by way of a plungers 40 passing through a generally radial bore in the hollow shaft 16 to cause the first yoke 18 to move radially in response to axial movement of the actuating rod and thereby vary the angular position of the first member 10 relative to the hollow shaft 16. Rotation of the hollow shaft 16 relative to the first member 10 causes the outer surface of the hollow shaft 16 to interact with the inner surface of the second yoke 20 to cause the angular position of the second member 14 to be varied in relation to the first member 10.

Abstract: A variable phase coupling for connecting a crankshaft to a camshaft comprises a drive member for connection to the crankshaft having helical grooves of a first pitch, a driven member for connection to the engine camshaft having helical grooves of a different pitch facing towards the grooves in the drive member, an intermediate member disposed between the drive and driven members having helical grooves on its inner and outer surfaces, a first set of balls engaging in the pairs of helical grooves comprising the helical grooves in the driven member and the facing grooves on one surface of the intermediate member, a second set of balls engaging in the pairs of helical grooves that comprise the grooves in the drive member and the facing grooves on the other surface of the intermediate member, and means for axially displacing the intermediate member relative to the drive and driven members.

Abstract: A variable phase coupling 10 is disclosed for connecting a crankshaft of an engine to a camshaft 16. The coupling 10 comprises a drive member 14, 18 having a first set of grooves 20, a driven member 26 having a second set of grooves 28 and mounted in a fixed axial position relative to the drive member 18 and an intermediate member 30 movable axially in relation to the drive and driven members. Grooves are arranged on the same side of the intermediate member to face the grooves of both the drive member and the driven member. A first set of balls 36 is engaged in the grooves 20 of the drive member 18 and the intermediate member 30 and a second set of balls 34 is engaged in the grooves 28 of the driven member 26 and the intermediate member 30 so as to transmit torque from the drive member to the driven member through the intermediate member.

Abstract: An internal combustion engine is described having a crankshaft (14) and a camshaft, the ends of which project from a front end of the engine. A hydraulically operable variable valve actuation mechanism is mounted on the camshaft at the front end of the engine for driving the camshaft. A front cover (10) that overlies the end of the camshaft projecting from the front end of the engine, includes passages (40, 42) that are connected to supply oil under pressure from an engine driven pump (16) to the variable valve actuation mechanism.

Abstract: A variable phase coupling for connecting a crankshaft to a camshaft (12) comprises a drive member (20) for connection to the crankshaft having grooves (40) of a first pitch, a driven member (14) for connection to the engine camshaft (12) having helical grooves (26) of a different pitch facing towards the grooves (40) in the drive member (20), balls (28) engaged in the two helical grooves (26, 40) and serving to couple the drive and driven members for rotation with one another, an intermediate member (16) disposed between the drive and driven members for rotation with one another, an intermediate member (16) disposed between the drive and driven members in contact with the balls (28, 34), and means (56) for displacing the intermediate member (16) relative to the drive and driven members. The displacement of the intermediate member (16) serves to move the balls relative to the helical grooves in the drive and driven members so as to vary the phase between the drive and driven members.