Method and device for thickening a plastically deformable hollow body wall of a hollow body, in particular in portions, and manufacturing method and machine for producing a hollow body

A device for thickening a plastically deformable hollow body wall of a hollow body, the hollow body wall extending in an axial direction along a cavity axis of a cavity of the hollow body, which cavity is delimited by the hollow body wall, the device comprising:

• an outer mold having a receptacle configured to receive the hollow body wall, said receptacle comprising a receptacle wall associated with an outer side of the hollow body wall, said receptacle wall forming, by means of a first partial length that extends in the axial direction, an outer supporting face for the hollow body wall and delimiting, by means of a second partial length that extends in the axial direction, an expansion space of the outer mold, the second partial length of the receptacle wall being offset radially outwardly relative to the first partial length of the receptacle wall, thus forming a widened region of the receptacle to form the expansion space,
• an inner supporting body associated with an inner side of the hollow body wall, said inner supporting body having a supporting body face that is associated with the inner side of the hollow body wall and extends in the axial direction and forms an inner supporting face for the hollow body wall, the inner supporting face of the inner supporting body being adapted to be arranged in the axial direction at a level of the outer supporting face and also at a level of the expansion space of the outer mold,
• two application members being configured to apply on the hollow body a compressive force in the axial direction at application points on the hollow body when the hollow body wall is effectively radially supported on the outer supporting face of the outer mold and on the inner supporting face of the inner supporting body, wherein the application members are configured to be moved relative to one another in the axial direction with a continuous compressing movement by means of a controllable motor drive, the application points on the hollow body being distanced from one another in the axial direction and the expansion space of the outer mold being arranged between the application points and one of the application members protruding radially outwardly relative to the outer side of the hollow body wall and delimiting the expansion space of the outer mold in the axial direction, wherein when the application members apply the compressive force on the hollow body, material of the hollow body wall between the application points is plasticised in a region of the expansion space of the outer mold and flows into the expansion space of the outer mold, thus thickening the hollow body wall,
• wherein the controllable motor drive is configured such that in addition to and simultaneously with the continuous compressing movement of the application members, an axial relative movement of the application members performing the continuous compressing movement and of the outer mold is performed in the axial direction with an extent of the expansion space of the outer mold in the axial direction increasing due to the axial relative movement,
• wherein the controllable motor drive is configured
• to axially move the application members performing the continuous compressing movement jointly and in the same direction and at different speeds, and
• to perform the axial relative movement of the application members performing the continuous compressing movement and of the outer mold by superimposing an axial movement of the outer mold in the axial direction on the continuous compressing movement of the application members,
• and
• wherein the controllable motor drive is force-controlled such that the controllable motor drive initiates the axial relative movement of the application members performing the continuous compressing movement and of the outer mold for increasing the extent of the expansion space of the outer mold in the axial direction once a limit value of the compressive force applied by the application members performing the continuous compressing movement on the hollow body at the application points is reached, the limit value indicating that the expansion space of the outer mold is filled completely with plasticized material of the hollow body wall.