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.

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.

An assembling apparatus places a retainer on a valve spring to surround an upper end of a valve stem. The apparatus includes an assembling head, and a moving unit configured to move the assembling head between the supply position of the retainer and an assembling position. The assembling head includes a holding unit configured to hold the retainer, and a push unit configured to push out the retainer. The push unit includes a push member supported to be able to advance/retreat along an elevating direction of the assembling head, and a biasing member configured to bias the push member in an advancing direction.

An assembling apparatus places a retainer on a valve spring to surround an upper end of a valve stem. The apparatus includes an assembling head, and a moving unit configured to move the assembling head between the supply position of the retainer and an assembling position. The assembling head includes a holding unit configured to hold the retainer, and a push unit configured to push out the retainer. The push unit includes a push member supported to be able to advance/retreat along an elevating direction of the assembling head, and a biasing member configured to bias the push member in an advancing direction.

A valve arrangement for a cylinder of an internal combustion engine arrangement includes a check valve configured to be positioned at an intake side port of the cylinder for controlling gas flow into the cylinder, wherein the valve arrangement further includes an intake valve arrangement positioned upstream from the check valve, and an actuating arrangement configured to controllably position the intake valve arrangement for closing the intake side port.

An assembling apparatus assembles a retainer by engaging a pair of cotter pieces with a valve stem. The apparatus includes an assembling head configured to hold, in a separated state, the pair of cotter pieces in the separated state prepared by a preparation unit and engage the pair of cotter pieces with the upper end of the valve stem. The head includes a storage member including a storage chamber, and a holding unit capable of pressing the pair of cotter pieces stored in the storage chamber against the upper end of the valve stem. The storage member includes first and second abutting portions. The second abutting portion positions the valve stem in the axial direction, and the first abutting portion positions the pair of cotter pieces in the axial direction.

An assembling apparatus assembles a retainer by engaging a pair of cotter pieces with a valve stem. The apparatus includes an assembling head configured to hold, in a separated state, the pair of cotter pieces in the separated state prepared by a preparation unit and engage the pair of cotter pieces with the upper end of the valve stem. The head includes a storage member including a storage chamber, and a holding unit capable of pressing the pair of cotter pieces stored in the storage chamber against the upper end of the valve stem. The storage member includes first and second abutting portions. The second abutting portion positions the valve stem in the axial direction, and the first abutting portion positions the pair of cotter pieces in the axial direction.

A retainer gripping device, configured to grip a retainer accommodating a set of cotters inside the retainer, includes a retainer gripping unit, a retainer supporting portion, and a cotter supporting portion. The retainer gripping unit is configured to grip the retainer. The retainer supporting portion is configured such that the retainer gripped by the retainer gripping unit is placed in a state in which the set of cotters are accommodated inside the retainer. The cotter supporting portion is configured to support lower end edge portions of the cotters accommodated inside the retainer in a state in which the lower end edge portions are lifted upward higher than a lower end edge portion of the retainer.

An internal combustion engine switches valve operation states, reduces or prevents wear of a cam and a rocker arm, and reduces the size of the cylinder head to ensure a sufficient valve lift amount. A valve spring retainer includes a cylindrical portion including a first through hole with an inner diameter decreases from the first end portion toward the second end portion, a cone-shaped portion including a second through hole with an inner diameter increases as it extends away from the second end portion of the cylindrical portion, and a flange portion extending radially outward from the cone-shaped portion. An outer diameter of the cylindrical portion is constant from the first end portion to the second end portion, and an outer diameter of the cone-shaped portion increases as it extends away from the second end portion.

An internal combustion engine switches valve operation states, reduces or prevents wear of a cam and a rocker arm, and reduces the size of the cylinder head to ensure a sufficient valve lift amount. A valve spring retainer includes a cylindrical portion including a first through hole with an inner diameter decreases from the first end portion toward the second end portion, a cone-shaped portion including a second through hole with an inner diameter increases as it extends away from the second end portion of the cylindrical portion, and a flange portion extending radially outward from the cone-shaped portion. An outer diameter of the cylindrical portion is constant from the first end portion to the second end portion, and an outer diameter of the cone-shaped portion increases as it extends away from the second end portion.