Rotor core molding method and system for molding a rotor core of an electric motor

A rotor core molding method for molding magnets in an unmolded rotor core to provide a molded rotor core for an electric motor, the unmolded rotor core including a rotor core body having magnet cavities distributed around a longitudinal axis of the rotor core body and magnets inserted in the magnet cavities, the magnet cavities extending along the longitudinal axis between opposing first and second rotor core ends of the rotor core body, the rotor core body having a rotor core height as measured between the first and second rotor core ends, the magnet cavities having an opening at one or both of the first and second rotor core ends to allow inserting the magnets and filling of the magnet cavities with a fluid molding material, the molded rotor core including the rotor core body having the magnets fixed in the magnet cavities by a cured molding material in the magnet cavities, the method comprising:

• employing a displacement mechanism configured to displace a first mold and a second mold of a rotor core molding system with respect to one another, the rotor core molding system comprising a frame, the first and second molds being disposed on the frame, the displacement mechanism defining
• an open configuration of the first and second molds for inserting the unmolded rotor core or a stack of unmolded rotor cores, that are stacked with respective first and second rotor core ends onto one another such that magnet cavities of the stacked rotor cores are in communication with one another, in between the first and second molds with the first and second rotor core ends directed towards respective ones of the first and second molds, and for removing the molded rotor core or a stack of molded rotor cores, respectively, from in between the first and second molds, and
• a closed configuration of the first and second molds for clamping the unmolded rotor core or the stack of unmolded rotor cores, respectively, in between the first and second molds and for passing a fluid molding material into the magnet cavities to provide the molded rotor core or the stack of molded rotor cores, respectively, clamped between the first and second molds,
• the displacement mechanism comprising a pre-adjustment arrangement and a mold closure arrangement different from the pre-adjustment arrangement, the pre-adjustment arrangement being configured to act between the frame and one of the first and second molds, the mold closure arrangement being configured to act between the frame and said one of the first and second molds to open and to close the first and second molds;
• employing the pre-adjustment arrangement to pre-adjust a distance between the first mold and the second mold in a preset open configuration of the first and second molds to a pre-adjusted distance corresponding to a clearance distance plus a height of the unmolded rotor core or the stack of unmolded rotor cores, respectively, to be processed to the molded rotor core or the stack of molded rotor cores, respectively, the pre-adjustment arrangement being configured to provide a relatively long-range distance movement, corresponding to variations in one or more of height of various types of rotor cores and a height of one or more rotor cores of various types of rotor cores;
• providing the unmolded rotor core or the stack of unmolded rotor cores between the first and second molds with the first and second rotor core ends directed towards respective ones of the first and second molds;
• employing the mold closure arrangement to close the first and second molds from the preset open configuration set by the pre-adjustment arrangement to the closed configuration by moving the first and second molds towards one another to clamp the unmolded rotor core or the stack of unmolded rotor cores with a predetermined pressure in between the first and second molds in the closed configuration, the mold closure arrangement being configured to provide a relatively short-range distance movement corresponding to the clearance distance, and the long-range distance and the short range distance are relative with respect to one another;
• providing a fluid molding material into the magnet cavities of the unmolded rotor core or the stack of unmolded rotor cores clamped between the first and second molds;
• letting the fluid molding material cure within the magnet cavities to provide one or more molded rotor cores;
• employing the mold closure arrangement to open the first and second molds from the closed configuration to the preset open configuration by moving the first and second molds away from one another;
• and
• removing the one or more molded rotor cores from between the first and second molds,
• wherein the mold closure arrangement has a mold closure pre-adjustment part that is attached to said one of the first and second molds and that is movable by the pre-adjustment arrangement in a decoupled state in which the mold closure pre-adjustment part is decoupled from the frame to allow adjusting the distance between the first and second molds to the pre adjusted distance, and that is movable with respect to the pre-adjustment arrangement in a coupled state in which the mold closure pre-adjustment part is coupled to the frame to allow opening and closing the first and second molds by the mold closure arrangement acting on said one of the first and second molds.