Abstract: A method of charging a hollow valve with metallic sodium includes providing a workpiece, as a semi-finished product for a hollow poppet valve, in which a cavity has an upward opening at a free end of a valve stem at a working position; inserting a nozzle into the opening to feed an initial inert gas into the cavity by jetting the inert gas from the nozzle; moving up the nozzle to put a holder between the workpiece and the nozzle, the holder holding a rod-like metallic sodium; and inserting the nozzle into a first end of the holder while an additional inert gas is jetted into the cavity from the nozzle to push down the rod-like metallic sodium along with the inert gas from a second end of the holder into the cavity of the workpiece.

Abstract: There is provided a method of charging a hollow valve with metallic sodium easily and swiftly without being oxidized over the surface of the metallic sodium and an apparatus therefor. The metallic sodium is fed into a cavity of the hollow valve in which a valve stem has a smaller diameter. A workpiece, a semi-finished product for a hollow poppet valve, is disposed at a working position where an opening is directed upward. A cavity of the workpiece is open at a free end of the valve stem. A nozzle is inserted into the opening. An inert gas is jetted from the nozzle and is fed into the cavity. Then, the nozzle is moved up, and a holder that holds the rod-like metallic sodium 10 is disposed between the workpiece and the nozzle. While the inert gas is jetted from the nozzle, the metallic sodium is pressed into the cavity of the workpiece.

Abstract: A method of producing a hollow valve comprises the step for forming material having a blind hole along its axis, the step for extruding the material in a shaping hole in a die downward and the step for lowering a lower part of a pin to an upper part of a smaller-diameter portion of the shaping hole to allow the material to plastically flow downward through a gap between the lower part of a pin and the smaller-diameter portion of the shaping hole thereby molding a primary intermediate of the hollow valve having a stem and a head at the upper end of the stem through which a hole is formed.

Abstract: A method of producing a hollow valve comprises the step for forming material having a blind hole along its axis, the step for extruding the material in a shaping hole in a die downward and the step for lowering a lower part of a pin to an upper part of a smaller-diameter portion of the shaping hole to allow the material to plastically flow downward through a gap between the lower part of a pin and the smaller-diameter portion of the shaping hole thereby molding a primary intermediate of the hollow valve having a stem and a head at the upper end of the stem through which a hole is formed.