A helical torsion valve spring assembly includes one or more helical torsion springs mounted within a frame and are held in a statically loaded state so that installation of a valve spring retainer can be easily performed. The entire helical torsion valve spring assembly is installed as a single part onto a cylinder head of an engine valvetrain. The helical torsion springs are mounted around a shaft to accurately locate the helical torsion springs so that the forces acting on the retainer and valve are precisely controlled. The assembly minimizes the size of the retainer, and applies only one bending mode to the helical torsion springs, which provides maximum utilization of the spring material and minimizes coil vibration. The assembly allows spring coils to be strategically packaged in the engine valvetrain to create space in critical areas.

Systems for valve actuation in internal combustion engines provide configurations for hydraulic lash adjusters and valve actuation valvetrain components that are particularly suitable for prevention of HLA jacking in dedicated cam environments including Type II valvetrain architectures. In one implementation, a lash adjuster loading component, which may comprise a stroke-limited spring biased piston associated with the main event valvetrain keeps the lash adjuster under a constant compressive force to prevent jacking.

A variable valve mechanism includes a first cam and a second cam, a main arm that drives a valve when swinging, a first sub arm that swings when pressed by the first cam, a second sub arm that swings when pressed by the second cam, and a switch device. The switch device includes a first switch pin that moves between a first coupled position between the main arm and the first sub arm and a first uncoupled position, and a second switch pin that moves between a second coupled position between the main arm and the second sub arm and a second uncoupled position. Both switch pins are arranged so as to be displaced from each other in positions where these switch pins do not overlap at least during a base circle phase in which base circles of both cams act.

A rocker arm includes a roller, a support shaft coaxially mounted in the roller, walls arranged along a rotation axis and having the roller therebetween and having through holes, respectively, through which end portions of the support shaft are inserted, and each of the walls having an inner surface opposite the roller, and holding members mounted in the respective walls. The holding member includes a tubular portion mounted in each through hole and disposed between an inner peripheral surface of the through hole and an outer surface of an end portion of the support shaft, a first stopper portion included at a first end of the tubular portion to be in contact with the inner surface of one of the walls, and a second stopper portion included at a second end of the tubular portion to be in contact with an end surface of one of the end portions.

A rocker arm includes a roller, a support shaft coaxially mounted in the roller and having a first end portion and a second end portion, walls including at least a first wall and a second wall arranged along the rotation axis and opposite each other with having the roller therebetween, the first wall having a first through hole through which the first end portion is inserted and the second wall having a second through hole through which the second end portion is inserted, and plate portions including at least a first plate portion and a second plate portion arranged opposite each other with having the first wall, the second wall and the support shaft therebetween. The first plate portion is in contact with a first end surface of the first end portion and the second plate portion is in contact with a second end surface of the second end portion.

A socket module for a compression release engine brake is provided between an exhaust rocker arm rotating with respect to a rocker arm shaft and a valve bridge in contact with an exhaust valve of an engine. In particular, the socket module includes: a housing which includes an inlet through which brake oil is introduced, a brake piston mounting portion, and a reset member mounting portion communicated with the brake piston mounting portion; a brake piston that is provided to be movable in the brake piston mounting portion; and a reset member that is provided in the reset member mounting portion and that discharges brake oil by selectively contacting a push pin coupled to an upper portion of a cylinder head of the engine.

A spring arrangement for a variable valve drive of an internal combustion engine includes an intermediate lever, a control shaft, a control shaft roller, a working cam contour, and a spring element. The intermediate lever comprises a contact surface, a camshaft roller which bears against a camshaft, and a slot roller which bears against a slotted guide. The control shaft roller is arranged on the intermediate lever to face away from the slotted guide. The control shaft roller bears against the control shaft. The working cam contour is formed at an end of the intermediate lever opposite the camshaft roller. The spring element comprises a force component on the contact surface in the direction of the camshaft and the slotted guide, and an end leg. The spring element loads the camshaft roller against the camshaft and the slot roller against the slotted guide. The end leg bears against the contact surface.

A valve gear for an engine includes cam shafts, first and second support walls, and rocker arms supported on the first and second support walls by supports. The supports switch among a plurality of support modes. The supports include first and second shaft holes, rocker shafts, tracks in the support walls, and return springs. The rocker shafts, move to positions where the support walls and the rocker arms are connected via the rocker shafts in a first support mode. In a second support mode, the rocker shafts move to positions where the connection between the support walls and the rocker arms is canceled. This makes it possible to provide a valve gear for an engine capable of smoothly switching a normal operation state support mode and cylinder resting state support mode, thus increasing the reliability of the operation.

A roller-type rocker arm had a function for transmitting a rotational motion of a cam to an intake and exhaust valve. The roller-type rocker arm includes a roller shaft, an inner ring roller slidably attached to an outer circumference surface of the roller shaft, and an outer ring roller slidably attached to an outer circumference surface of the inner ring roller. The inner ring roller is made of a resin material.

A rocker arm includes a pair of sidewalk disposed along a heightwise direction so as to be opposed to each other. The sidewalk define a space to house a roller and have opposed portions extending in the heightwise direction relative to adjacent portions which are adjacent to the opposed portions. The opposed portions have thinner portions having smaller thicknesses than the adjacent portions.