A production method for a cylinder device includes a first liquid injection step of injecting a first predetermined amount of working fluid L into the inner cylinder, a first piston rod insertion step of inserting an assembly between the piston rod and the piston into the inner cylinder to dispose the piston at a predetermined position inside the inner cylinder, a second liquid injection step of injecting a second predetermined amount of the working fluid into an upper side of the piston inside the inner cylinder, and a closing step of closing the opening of the outer cylinder with the closing member.

A production method for a cylinder device includes a first liquid injection step of injecting a first predetermined amount of working fluid L into the inner cylinder, a first piston rod insertion step of inserting an assembly between the piston rod and the piston into the inner cylinder to dispose the piston at a predetermined position inside the inner cylinder, a second liquid injection step of injecting a second predetermined amount of the working fluid into an upper side of the piston inside the inner cylinder, and a closing step of closing the opening of the outer cylinder with the closing member.

A piston rod unit and a method for producing a piston rod unit, or a shaft, in light-weight construction, with a rod which is hollowly-drilled by means of a deep bore into the rod shank, and the resulting rod opening is closed subsequently by means of a forging process.

A piston rod unit and a method for producing a piston rod unit, or a shaft, in light-weight construction, with a rod which is hollowly-drilled by means of a deep bore into the rod shank, and the resulting rod opening is closed subsequently by means of a forging process.

A piston for an internal combustion engine may include a piston crown, a piston body, and a ring portion. The piston body may have a radially outermost piston outer surface, which may emanate from the piston crown and extend axially and in a circumferential direction. The ring portion may be disposed axially spaced apart from the piston crown. The ring portion may extend axially and in the circumferential direction. The ring portion may include a ring carrier with a ring groove configured to receive a piston ring. The ring portion may further include a radially outer ring portion outer surface that extends in the circumferential direction. The ring portion outer surface may be disposed radially to an inside relative to the piston outer surface. The piston outer surface may extend elliptically in the circumferential direction. The ring portion outer surface may extend rotation-symmetrically in the circumferential direction.

A method for producing a piston may include providing a blank of a piston base member with an outer peripheral joining face, an inner peripheral joining face which may be expanded in a direction of a base region of a combustion bowl, and a lower cooling channel portion which may extend between the outer and inner peripheral joining faces, wherein at least one of (i) at least one of the outer and inner peripheral joining faces and (ii) the lower cooling channel portion may be not subsequently processed. The method may then include providing a blank of a piston ring element with an outer annular joining face, an inner annular joining face, and an upper cooling channel portion which may extend between the outer and inner annular joining faces, wherein at least one of (i) at least one of the outer and inner annular joining faces and (ii) the upper cooling channel portion may be not subsequently processed. The method may then include joining the blanks via the outer and inner peripheral joining faces and the outer and inner annular joining faces to form a piston blank in such a manner that, at least in the base region of the combustion bowl, a part-region of the expanded inner peripheral joining face of the blank of the piston base member may remain free. The method may further include subsequently at least partially processing the piston blank to form the piston with the part-region of the expanded inner peripheral joining face being removed.

A method for producing a piston may include providing a blank of a piston base member with an outer peripheral joining face, an inner peripheral joining face which may be expanded in a direction of a base region of a combustion bowl, and a lower cooling channel portion which may extend between the outer and inner peripheral joining faces, wherein at least one of (i) at least one of the outer and inner peripheral joining faces and (ii) the lower cooling channel portion may be not subsequently processed. The method may then include providing a blank of a piston ring element with an outer annular joining face, an inner annular joining face, and an upper cooling channel portion which may extend between the outer and inner annular joining faces, wherein at least one of (i) at least one of the outer and inner annular joining faces and (ii) the upper cooling channel portion may be not subsequently processed. The method may then include joining the blanks via the outer and inner peripheral joining faces and the outer and inner annular joining faces to form a piston blank in such a manner that, at least in the base region of the combustion bowl, a part-region of the expanded inner peripheral joining face of the blank of the piston base member may remain free. The method may further include subsequently at least partially processing the piston blank to form the piston with the part-region of the expanded inner peripheral joining face being removed.

A method for producing a piston for an internal combustion engine may include producing a piston upper part including a piston top, at least parts of a ring section, and at least part of a cooling channel, producing a piston lower part and closing the part of the cooling channel arranged in the piston upper part via an additive method, and finish-machining the piston. Finish-machining the piston may include producing at least one annular groove in a ring support for receiving a piston ring.

A method for producing a piston for an internal combustion engine may include producing a piston upper part including a piston top, at least parts of a ring section, and at least part of a cooling channel, producing a piston lower part and closing the part of the cooling channel arranged in the piston upper part via an additive method, and finish-machining the piston. Finish-machining the piston may include producing at least one annular groove in a ring support for receiving a piston ring.

A production method for a cylinder device includes a first liquid injection step of injecting a first predetermined amount of working fluid into the inner cylinder, a first piston rod insertion step of inserting an assembly of the piston rod and the piston into the inner cylinder to dispose the piston at a predetermined position inside the inner cylinder, a second liquid injection step of injecting a second predetermined amount of the working fluid into an upper side of the piston inside the inner cylinder, and a closing step of closing the opening of the outer cylinder with the closing member.