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.

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.

An internal combustion engine 5 includes an intake valve spring 60 including a closely-wound section 62 and a sparsely-wound section 63. The closely-wound section 62 is provided so that elemental wire portions thereof are closely in contact with each other in the direction of the coil axial line L1 while an intake valve closes an intake port. The sparsely-wound section 63 is provided so that elemental wire portions thereof are spaced apart from each other in the direction of the coil axial line L1 while the intake valve closes the intake port. The coil outer diameter D62 of at least a part of the closely-wound section 62 is smaller than the coil outer diameter D63 of at least a part of the sparsely-wound section 63.

An internal combustion engine 5 includes an intake valve spring 60 including a closely-wound section 62 and a sparsely-wound section 63. The closely-wound section 62 is provided so that elemental wire portions thereof are closely in contact with each other in the direction of the coil axial line L1 while an intake valve closes an intake port. The sparsely-wound section 63 is provided so that elemental wire portions thereof are spaced apart from each other in the direction of the coil axial line L1 while the intake valve closes the intake port. The coil outer diameter D62 of at least a part of the closely-wound section 62 is smaller than the coil outer diameter D63 of at least a part of the sparsely-wound section 63.

A valve spring collar (10) for supporting spring forces of closing springs (40) that act on gas exchange valves (32) in an internal combustion engine has a plate-shaped main body (12). A through opening (14) leads through the main body (12) for receiving and attaching a valve stem (36) of the gas exchange valve (32). The valve spring collar (10) also has at least one cavity (16). A method for producing the valve spring collar (10) includes at least one additive production method step.

A valve spring collar (10) for supporting spring forces of closing springs (40) that act on gas exchange valves (32) in an internal combustion engine has a plate-shaped main body (12). A through opening (14) leads through the main body (12) for receiving and attaching a valve stem (36) of the gas exchange valve (32). The valve spring collar (10) also has at least one cavity (16). A method for producing the valve spring collar (10) includes at least one additive production method step.

An actuating system of an engine valve comprises a movable member, for example, in the form of a master piston controlled by a cam of a camshaft. A slave piston is hydraulically controlled by the master piston by means of a volume of pressurized fluid, to open said engine valve against the action of a return spring. The system also comprises an auxiliary device for applying an additional force to the engine valve to keep the engine valve in a closed position. The auxiliary device is configured or controlled in such a way that the total force tending to keep the engine valve in its closed position varies during each rotation cycle of the cam. The total force is higher at least in one part of the rotation cycle of the cam wherein the engine valve must remain in its closed position, and is, instead, reduced at least in one part of the rotation cycle of the cam wherein the engine valve is not in its closed position.

An actuating system of an engine valve comprises a movable member, for example, in the form of a master piston controlled by a cam of a camshaft. A slave piston is hydraulically controlled by the master piston by means of a volume of pressurized fluid, to open said engine valve against the action of a return spring. The system also comprises an auxiliary device for applying an additional force to the engine valve to keep the engine valve in a closed position. The auxiliary device is configured or controlled in such a way that the total force tending to keep the engine valve in its closed position varies during each rotation cycle of the cam. The total force is higher at least in one part of the rotation cycle of the cam wherein the engine valve must remain in its closed position, and is, instead, reduced at least in one part of the rotation cycle of the cam wherein the engine valve is not in its closed position.