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,

• wherein an unmolded rotor core (10A) comprises a rotor core body (11) having magnet cavities (12) distributed around a longitudinal axis (A) of the rotor core body and magnets (13) inserted in the magnet cavities, the magnet cavities extend along the longitudinal axis between opposing first and second rotor core ends (11.1, 11.2) of the rotor core body, the rotor core body has a rotor core height (h) as measured between the first and second rotor core ends, and the magnet cavities have an opening (12.1) 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,
• wherein a molded rotor core (10B) comprises the rotor core body (11) having the magnets fixed in the magnet cavities by a cured molding material (14) in the magnet cavities, and
• wherein the method comprises
• employing a displacement mechanism for displacing a first mold (110) and a second mold (120) of a rotor core molding system (100) with respect to one another, and which defines
• an open configuration of the first and second molds for inserting an unmolded rotor core or a stack of unmolded rotor cores, that are stacked with their 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 a 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 a molded rotor core or a stack of molded rotor cores, respectively, clamped between the first and second molds,
• wherein the displacement mechanism comprises a pre-adjustment arrangement (130) and a mold closure arrangement (140);
• employing the pre-adjustment arrangement (130) to pre-adjust a distance between the first mold (110) and the second mold (120) in a preset open configuration of the first and second molds to a pre-adjusted distance (HO) corresponding to a clearance distance (d) plus a height (H) 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, wherein the pre-adjustment arrangement is configured to provide a relatively long-range distance movement, especially corresponding to variations in height of various types of rotor cores and/or a height of one or more rotor cores of various types of rotor cores;
• providing an unmolded rotor core or a 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 (140) to close the first and second molds from the preset open configuration to the closed configuration by moving the first and second molds towards one another to clamp the unmolded rotor core(s) with a predetermined pressure in between the first and second molds in the closed configuration, wherein the mold closure arrangement is configured to provide a relatively short-range distance movement corresponding to the clearance distance (d), 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(s) 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 (160) 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 molded rotor core(s) from between the first and second molds.