ROTOR CORE MANUFACTURING METHOD AND ROTOR CORE MOLDING SYSTEM

Abstract

A rotor core manufacturing method and manufacturing system allows for molding permanent magnets in an unformed rotor core to provide a formed rotor core for an electric motor. The unformed rotor core includes a rotor core body having a shaft, a central through hole along a longitudinal axis, magnet cavities distributed around the longitudinal axis, and magnets inserted in the magnet cavities, the shaft is disposed in the central through hole so as to protrude from the central through hole, and the formed rotor core includes a rotor core body having magnets fixed in the magnet cavities by hardened molding material. The method includes inserting the unformed rotor core between a first mold and a second mold of a rotor core molding system, moving the first mold and the second mold toward each other to clamp the rotor core body of the unformed rotor core at a predetermined pressure and closing the first mold and the second mold, providing a fluid molding material in the magnet cavities, hardening the fluid molding material in the magnet cavities into the formed rotor core, and opening the first mold and the second mold to remove the formed rotor core.

Description

[Technical field]

[0001]

[0001] The present invention relates to a rotor core manufacturing method and system for molding magnets within an unformed rotor core to provide a molded rotor core for an electric motor, the unformed rotor core comprising a rotor core body having a central through hole extending along and about a longitudinal axis of the rotor core body, magnet cavities distributed about the longitudinal axis, and magnets inserted in the magnet cavities, the magnet cavities and central through hole extending along the longitudinal axis between opposing first and second rotor core body ends of the rotor core body, and the magnet cavities having openings at one or both of the first and second rotor core body ends to allow the magnet cavities to be filled with a fluid molding material, and the molded rotor core comprises a rotor core body having magnets fixed in the magnet cavities by hardened molding material in the magnet cavities. The system includes a first die and a second die arranged to enable clamping of at least one unformed rotor core between the first die and the second die. [Background technology]

[0002]

[0002] Such rotor core molding systems and corresponding methods are generally known. An unformed rotor core, typically a set of stacked individual metal laminations, is provided between dies and then a clamping pressure is set. A fluid molding material is provided into the magnet cavity of the unformed rotor core clamped between a first die and a second die, and the fluid molding material can then be cured in the magnet cavity to provide a formed rotor core. The first die and the second die are then opened, and the rotor core is removed from between the first die and the second die.

[0003]

[0003] In known systems and methods, the unformed rotor core is first provided on a support plate, which generally has a pin provided in the central through hole of the rotor core. The rotor core can have several sets of lamellae, each set having magnet cavity segments slightly displaced with respect to the magnet cavity segments of the adjacent sets of lamellae. The central pin of the support plate aligns the various lamellae and their sets and maintains the alignment during the processing of the rotor core. However, providing the rotor core on the support plate and pins and removing the rotor core from the support plate and pins after processing requires very careful attention and dedicated handling of the rotor core. The integrity of the rotor core should be maintained, for example, after the forming of the magnets in the magnet cavities. The steps of providing the rotor core to and removing it from the support plate and pins are limiting steps in the processing efficiency and quality of the rotor core. Summary of the Invention

[0004]

[0004] An object of the present invention is to provide an improved efficiency and speed of rotor core manufacturing method and system for molding magnets into an unformed rotor core to provide a formed rotor core for an electric motor.

[0005]

[0005] Another or alternative object of the present invention is to provide a rotor core manufacturing method and system for molding magnets into an unformed rotor core to provide a formed rotor core for an electric motor that better protects the quality aspects of the rotor core.

[0006] In one aspect, the present invention provides a rotor core manufacturing method for molding permanent magnets into an unformed rotor core to provide a formed rotor core for an electric motor, comprising: The unformed rotor core comprises a shaft of an electric motor and a rotor core body having a central through hole extending along and around a longitudinal axis of the rotor core body, magnet cavities distributed around the longitudinal axis, and permanent magnets inserted into the magnet cavities, wherein the shaft of the electric motor is disposed in the central through hole, the magnet cavities and the central through hole extend along the longitudinal axis between opposing first and second rotor core body ends of the rotor core body, and the magnet cavities have openings at one or both of the first and second rotor core body ends for filling the magnet cavities with a fluid molding material, and the shaft protrudes from the central through hole of the rotor core body relative to one or both of the rotor core body ends; The molded rotor core includes a rotor core body having a permanent magnet secured in a magnet cavity by hardened molding material in the magnet cavity; The method is: Providing an unformed rotor core; providing a rotor core pressure molding system having a first mold and a second mold, the first mold and the second mold being configured and arranged, in an open configuration of the first mold and the second mold, to insert an unformed rotor core between the first mold and the second mold with a first rotor core body end and a second rotor core body end facing the first mold and the second mold, respectively, along a clamping direction, and, in a closed configuration of the first mold and the second mold, to clamp a rotor core body of the unformed rotor core between the first mold and the second mold to provide pressure along the clamping direction to the rotor core body clamped by the first mold and the second mold, and to provide fluid molding material to magnet cavities of the unformed rotor core clamped between the first mold and the second mold, wherein the first mold and the second mold are configured and arranged to insert an unformed rotor core between the first mold and the second mold with a first rotor core body end and a second rotor core body end facing the first mold and the second mold, respectively, along a clamping direction, a first die configured to receive therein a shaft protruding from the central through hole of the rotor core body relative to each rotor core body end, the first die having a recess or opening therein for receiving the shaft protruding from the central through hole of the rotor core body relative to each rotor core body end, and the recess or opening of the first die being dimensioned such that when the rotor core is clamped between the first die and the second die, the shaft does not contact the first die and exert a clamping force; and a second die having therein a recess or opening therein for receiving the shaft protruding from the central through hole of the rotor core body relative to each rotor core body end, and the recess or opening of the second die being dimensioned such that when the rotor core is clamped between the first die and the second die, the shaft does not contact the second die and exert a clamping force. inserting an unformed rotor core between a first die and a second die of a rotor core molding system with the first rotor core body end and the second rotor core body end facing the respective first die and second die in an open configuration of the first die and the second die; closing the first and second dies from an open configuration to a closed configuration by moving the first and second dies toward each other to clamp a rotor core body of the unformed rotor core with a predetermined pressure between the first and second dies in the closed configuration; providing a fluid molding material into magnet cavities of an unformed rotor core body clamped between a first die and a second die; curing the fluid molding material within the magnet cavities to provide a molded rotor core; opening the first and second molds to an open configuration by moving the first and second molds away from each other; Removing the molded rotor core from between the first die and the second die. Includes.

[0007]

[0007] In one embodiment, rotor core end caps are provided at one or both of the first rotor core body end and the second rotor core body end, one or both of the rotor core end caps having cap openings therein that are associated with the magnet cavities of the rotor core body for one or both of providing fluid molding material into the magnet cavities through the respective cap openings and allowing air to escape from the magnet cavities while the magnet cavities are being filled with the fluid molding material.

[0008] In one embodiment, a fluid molding material is provided within the magnet cavity such that the fluid molding material at least partially fills the cap opening of one or both end caps.

[0009] In another aspect, the present invention provides a rotor core pressing system for molding permanent magnets into an unformed rotor core to provide a formed rotor core for an electric motor, the system comprising: The unformed rotor core comprises a shaft of an electric motor and a rotor core body having a central through hole extending along and around a longitudinal axis of the rotor core body, magnet cavities distributed around the longitudinal axis, and permanent magnets inserted into the magnet cavities, wherein the shaft of the electric motor is disposed in the central through hole, the magnet cavities and the central through hole extend along the longitudinal axis between opposing first and second rotor core body ends of the rotor core body, and the magnet cavities have openings at one or both of the first and second rotor core body ends for filling the magnet cavities with a fluid molding material, and the shaft protrudes from the central through hole of the rotor core body relative to one or both of the rotor core body ends; The molded rotor core comprises a rotor core body having a permanent magnet secured in a magnet cavity by a hardened molding material in the magnet cavity; and The system includes a first mold and a second mold, the first mold and the second mold being constructed and arranged to, in an open configuration of the first mold and the second mold, insert an unformed rotor core between the first mold and the second mold with a first rotor core body end and a second rotor core body end facing the first mold and the second mold, respectively, along a clamping direction, and to, in a closed configuration of the first mold and the second mold, clamp a rotor core body of the unformed rotor core between the first mold and the second mold to provide pressure along the clamping direction to the rotor core body clamped by the first mold and the second mold, and provide fluid molding material to magnet cavities of the unformed rotor core clamped between the first mold and the second mold, where the first mold and the second mold are configured and arranged to clamp a rotor core body of the unformed rotor core between the first mold and the second mold with a first rotor core body end and a second rotor core body end facing the first mold and the second mold, respectively, along a clamping direction. The first die is configured to receive therein a shaft protruding from the central through hole of the rotor core body, the first die having a recess or opening therein for receiving the shaft protruding from the central through hole of the rotor core body at each rotor core body end, and the recess or opening of the first die is dimensioned such that the shaft does not contact the first die and apply a clamping force when the rotor core is clamped between the first die and the second die, and the second die having a recess or opening therein for receiving the shaft protruding from the central through hole of the rotor core body at each rotor core body end, and the recess or opening of the second die is dimensioned such that the shaft does not contact the second die and apply a clamping force when the rotor core is clamped between the first die and the second die.

[0010]

[0010] In one embodiment, one or both of the first and second molds include a plurality of cylinder reservoirs and a plunger associated with each of the plurality of cylinder reservoirs for providing fluid molding material within the magnet cavities of the rotor core body of the unformed rotor core, and a cylinder reservoir of the plurality of cylinder reservoirs is positioned around the recess or opening to receive a shaft protruding from a central through hole of the rotor core body. [Brief description of the drawings]

[0011] Further features and advantages of the present invention will become apparent from the description of the present invention by non-limiting and non-exclusive embodiments. These embodiments should not be interpreted as limiting the scope of protection. Those skilled in the art will understand that they can conceive and implement other alternatives and equivalent embodiments of the present invention without departing from the scope of the present invention. The embodiments of the present invention will be described with reference to the accompanying drawings, in which similar or identical reference symbols indicate similar, identical or corresponding parts. [Figure 1] FIG. 1 is a cross-sectional view of an electric motor. [Figure 2A] FIG. 2 illustrates an unformed rotor core without the shaft of an electric motor, but with magnets inserted into the magnet cavities of the rotor core body. [Figure 2B] FIG. 2 shows an unformed rotor core having a shaft and magnets inserted into the magnet cavities. [Figure 2C] FIG. 2C shows a molded rotor core corresponding to the unmolded rotor core of FIG. 2B, with magnets secured within the magnet cavities by hardened molding material. [Diagram 3] FIG. 2 illustrates a rotor core between a first die and a second die of a molding apparatus. [Figure 4A] 1A-1C illustrate steps in a molding process for molding a magnet into a magnet cavity using a molding apparatus. [Figure 4B] FIG. 13 illustrates another step in the molding process for molding a magnet into a magnet cavity using a molding apparatus. [Figure 4C] FIG. 13 illustrates yet another step in the molding process for molding a magnet into a magnet cavity using a molding apparatus. [Figure 4D] FIG. 13 illustrates yet another step in the molding process for molding a magnet into a magnet cavity using a molding apparatus. [Figure 5A]FIG. 2 is a top perspective view of an upper portion of a first mold of a molding apparatus. [Figure 5B] FIG. 2 is a cross-sectional view of the top of a first mold of a molding apparatus. [Figure 6A] FIG. 2 is a top perspective view of a second mold of the molding apparatus. [Figure 6B] FIG. 2 is a bottom perspective view of a second mold of the molding apparatus. [Figure 6C] FIG. 4 is a cross-sectional view of a second mold of the molding apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Detailed Description of the Embodiments

[0012] Figure 1 shows a cross section of an electric motor 1, in particular an electric motor for driving a vehicle such as an automobile, the electric motor having a rotor 10 and a stator 20. The stator has electrical windings 21 for currents that induce magnetic fields that interact with the magnetic fields of the permanent magnets 13 of the rotor 10 to drive the rotor core 10 in rotation. In general, electric motors can have a wide variety of configurations for the electrical windings and magnets. An axle or shaft 16, mounted in a central opening or central through-hole 15 of the rotor 10 along an axis A, is driven in rotation by driving the rotor 10 in rotation. The shaft 16 is the drive shaft of the electric motor 1 for transmitting the rotation of the electric motor to a driven assembly.

[0013]

[0013] Figure 2B shows an embodiment of a rotor core 10A comprising a rotor core body 11 having magnet cavities 12 distributed around the longitudinal axis A of the rotor core and rotor core body. The magnet cavities 12 extend along the longitudinal axis A between opposing first and second rotor core ends 11.1 and 11.2 of the rotor core body. The rotor core body has a height measured between the first and second rotor core ends and a central opening 15 for receiving a mandrel 16 therein. Each of the magnet cavities 12 has an opening 12.1 at one or both of the first and second rotor core ends. The rotor body 11 is composed of four rotor core body segments 11A, each having a magnet cavity segment 12A of height h, in the illustrated embodiment. In the illustrated embodiment, the magnet cavity segments of adjacent rotor core body segments are slightly offset from each other, but are in contact to allow the passage of fluid molding material between the adjacent magnet cavity segments. The magnet cavity segments 12A in contact with each other form the magnet cavity 12. The permanent magnets 13 are inserted into the magnet cavity segments 12A of the magnet cavities 12, and then the rotor core segments 11A are stacked as shown in FIG. 2A. Then, the mandrel 16 is provided in the central through hole 15 of the rotor core body and protrudes from the central through hole of the rotor core body relative to the rotor core body ends 11.1, 11.2 to reach the unformed rotor core of FIG. 2B. FIGS. 2A and 2B show the permanent magnets 13 inserted into the magnet cavity segments of the respective magnet cavities 12 of the rotor core body 11, and FIG. 2B shows the mandrel 16 additionally provided in the central through hole 15. The permanent magnets 13 are not yet fixed in the magnet cavities 12 of the rotor core 10A shown in FIG. 2B. In the next manufacturing step of the rotor core, the magnets 13 are fixed in their respective magnet cavities 12 by introducing a fluid molding material, such as a suitable thermosetting epoxy resin, into the magnet cavities to fill any voids in the magnet cavities with the fluid molding material. The fluid molding material is then cured to fix the magnets in the magnet cavities. Figure 2C shows the cured molding material 14B in the magnet cavities.Fig. 2B shows an unformed rotor core 10A, and Fig. 2C shows a formed rotor core 10B. Fig. 2A shows the unformed rotor core before the shaft 16 is inserted into the central through hole 15. The formed rotor core 10B is basically a rotor that is provided inside the stator when assembling an electric rotor. Rotor core end caps may be provided, for example, at the rotor core body ends 11.1, 11.2 as part of the rotor core.

[0014]

[0014] A pressure forming assembly for pressure forming the rotor core described with reference to Figures 2A, 2B and 2C is shown in Figure 3. The pressure forming assembly comprises a first die 110 as a bottom die and a second die 120 as a top die. Figure 3 shows the still unformed rotor core of Figure 2B, but with the addition of rotor core end caps 17. The rotor core end caps 17 are provided on both rotor core body ends 11.1, 11.2 of the rotor core body. The rotor core end caps are also provided as part of the unformed rotor core and are in place during forming of the magnets in the magnet cavities. To that end, the rotor core end caps have openings 17.1 therein associated with the respective magnet cavities 12 in the rotor core body. The end caps are provided on the rotor core segments such that the openings 17.1 of the end caps 17 are aligned with the magnet cavities 12. The rotor core also includes end caps to form a total height H of the stacked rotor core segments 11A, rotor core end caps 17, and runner gate plate 125. The runner gate plate 125 rests on top of the stack of rotor core segments and rotor core end caps. The runner gate plate has a central opening 129.1 for receiving the shaft 16 that protrudes through a central through hole in the rotor core body. Gates 127 of the runner gate plate 125 are aligned with the magnet cavities 12 and openings 17.1 in the rotor core end caps 17 at the top surface of the rotor core.

[0015]

[0015] Both the bottom die 110 and the top die 120 include recesses 119, 129 for receiving the shaft 16 protruding from the central through hole of the rotor core body. The second (top) die 120 further includes a plurality of cylinder reservoirs 122 and plungers 121 associated with each cylinder reservoir for providing fluid molding material from the cylinder reservoirs into the magnet cavities 12 of the rotor core body of the unformed rotor core. The cylinder reservoirs 122 of the plurality of cylinder reservoirs are disposed around the recess 129 for receiving the shaft 16 protruding from the central through hole of the first rotor core body end.

[0016] In use, in the illustrated embodiment, the first (bottom) die 110, with the unformed rotor core and runner plate 125 resting thereon, moves upward and is pressed against the second (top) die 120. Figure 3 shows the rotor core body with the rotor core end caps clamped and pressed between the first die 110 and the second die 120. The runner gate plate 125 becomes part of the second die 120 when the rotor core is clamped and pressed between the first die 110 and the second die 120 along a clamping direction parallel to the longitudinal direction of the shaft or mandrel 16. The molding material is brought into the cylinder reservoir 122 of the second mold 120 and heated to provide it in a fluid state, and then the plunger 121 is moved downward to transfer the fluid molding material 14A through the channel 126 and the gate 127 of the runner gate plate 125, which is now part of the second mold, into the magnet cavity 12, particularly into the magnet cavity segment 12A of the top unformed rotor core segment 11A. Since the magnet cavity segments 12A are aligned, the fluid molding material passes from the magnet cavity segment 12A of the top rotor core body segment to the bottom magnet cavity segment of the unformed rotor core body segment, and finally fills the space in the magnet cavity 12 that is not occupied by the magnets 13. The molding material then hardens and becomes solid, fixing the magnets 13 in the magnet cavities 12. The rotor core body now becomes the formed rotor core body 10B. The method and system allows for precise positioning of the shaft 16 within the rotor core body 11 while maintaining the integrity of the shaft and rotor core body assembly while pressing the permanent magnets 13 tightly in place within the magnet cavities 12 of the rotor core body. To quickly and fully fill the relatively small space available in the magnet cavities while the magnets are being inserted, a high filling pressure, and therefore clamping pressure, is required to obtain a reliable and positionally stable fixation of the permanent magnets within the cavities. All this results in a high performance, highly reliable and very stable electric motor.By having the shaft well positioned within the rotor core body prior to compaction, the magnets have an additional advantage in terms of throughput, as does having the end caps in place during compaction. The end caps are also very efficiently and securely secured to the rotor core body ends to aid in any efficient post processing of the rotor core and a well functioning electric motor.

[0017] 4A, 4B, 4C and 4D show an embodiment of the rotor core molding method and system 100 of the present invention. The rotor core molding system comprises a frame 150 and a first die 110 and a second die 120 disposed on the frame. The first die 110 is movable relative to the frame 150 via a displacement device 130 having a table 132 and an actuator 131, and the second die 120 is fixedly attached to the frame. The displacement device 130 is presented only very diagrammatically and may comprise any suitable device for moving the first die 110 up and down. When closing the first die and the second die of the die assembly, the first die 110 moves upward toward the second die 120. When opening the first die and the second die of the die assembly, the first die moves downward away from the second die. In the open configuration shown in FIG. 4A, an unformed rotor core can be provided on a first mold 110. FIG. 4B shows a situation in which an unformed rotor core 10A is provided on a rotor core body on the first mold. The shaft protruding downward from the central through hole of the rotor core body is received in a recess of the first mold. The rotor core body is provided with a runner gate plate, and the rotor core is placed on the first mold 110 together with the runner gate plate. Then, as shown in FIG. 4C, the first mold is moved upward until the rotor core body with the runner gate plate is pressed against the second mold 120, and the shaft protruding upward from the central through hole of the rotor core body is received in a recess of the second mold 120. Here, the runner gate plate is effectively part of the second mold. The molding material provided in the cylinder reservoir is heated to become a fluid, and is then pressed by the respective plungers from the cylinder reservoir into the magnet cavity through the channel and gate in the runner gate plate. Once the molding material has hardened, the first and second molds of the mold assembly are opened to an open configuration by moving the first and second molds 110 and 120 away from each other, as shown in FIG. 4D, allowing the molded rotor core to be removed from the first mold 110.The runner gate plate, still on top of the rotor core, is removed from the first mold along with the rotor core. The runner gate plate is removed from the formed rotor core elsewhere and prepared for reuse in the next molding process.

[0018]

[0018] FIG. 5A shows a top perspective view of one embodiment of a replaceable top 115 of the first mold 110, which is a replaceable part of the first mold and is mounted on the bottom 116 of the first mold 110. The top and bottom are shown in schematic form in FIGS. 4A-4D. FIG. 5B shows a cross section of the top of the first mold. The top 115 can be configured for the type of rotor core to be processed in the molding system 100. In the illustrated embodiment, the top 115 can be mounted on the bottom 116 of the first mold by a sliding device and can be removed from the bottom 116. The top 115 of the first mold 110 has a central opening 119.1, which is part of the recess 119 of the first mold when the top 115 is mounted on the bottom 116 of the first mold. The bottom also has a part of the recess 119. Alternatively, the recess 119 may only be provided by an opening 119.1 in the top 115 of the first mold 110, if the bottom 116 has a closed flat top surface. The recess 119 receives the shaft 16 that protrudes downward from the rotor core body. The bottom 116 of the first mold 110 has a heating element for heating the rotor core from below during the molding process. As mentioned above, the top 115 of the first mold is specifically configured for the rotor core to be machined. The top 115 has ventilation channels 115.1, the top openings of which are associated with and aligned with the magnet cavities 12 of the rotor core to be machined in the molding system, allowing air to escape from the magnet cavities while the fluid molding material is being introduced to the top surface of the magnet cavities.

[0019] 6A and 6B show top and bottom perspective views, and FIG. 6C shows a cross-sectional view, of one embodiment of the second mold 120. A plurality of cylinder reservoirs 122 are provided around a recess 129 for receiving a shaft 16 protruding upward from a rotor core body process in a molding system. The respective plungers associated with the cylinder reservoirs are not shown in FIG. 6A. The respective plungers enter the cylinder reservoirs 122 from above. The open bottom end of the cylinder reservoirs can be seen in FIG. 6B. The second mold 120 has a heating element for heating the rotor core from above and for heating the molding material in the cylinder reservoirs during the molding process. When the fluid molding material is pushed out of the cylinder reservoirs by the respective plungers, it leaves the cylinder reservoirs from the open bottom end and enters a channel 126 and then a gate 127 of a runner gate plate 125, which is part of the second mold during the molding process. The central opening 129.1 in the runner gate plate 125, which is part of the second mold 120 during the molding process, is part of the recess 129 in the second mold 120. In some embodiments, the runner gate plate opening 129.1 may even completely provide the second mold recess 129.

Claims

1. 1. A rotor core manufacturing method for molding permanent magnets into an unformed rotor core to provide a formed rotor core for an electric motor, comprising the steps of: An unformed rotor core (10A) comprises a shaft (16) of the electric motor (1) and a rotor core body (11) having a central through hole (15) extending along and around a longitudinal axis (A) of the rotor core body, magnet cavities (12) distributed around the longitudinal axis (A), and permanent magnets (13) inserted into the magnet cavities, wherein the shaft of the electric motor is disposed in the central through hole and the magnet cavities and the central through hole are disposed around the longitudinal axis (A). a through hole extends along the longitudinal axis between opposing first and second rotor core body ends (11.1) and (11.2) of the rotor core body, and the magnet cavities have openings (12.1) at one or both of the first and second rotor core body ends for filling the magnet cavities with a fluid molding material, and the shaft protrudes from the central through hole of the rotor core body relative to one or both of the rotor core body ends; A molded rotor core (10B) includes the rotor core body (11) having the permanent magnets fixed in the magnet cavities by hardened molding material (14) in the magnet cavities; and Providing an unformed rotor core; providing a rotor core pressure molding system (100) having a first mold (110) and a second mold (120), the first mold (110) and the second mold (120) being configured and arranged to, in an open configuration of the first mold and the second mold, insert the unformed rotor core between the first mold and the second mold with the first rotor core body end and the second rotor core body end facing the first mold and the second mold, respectively, along a clamping direction, and to, in a closed configuration of the first mold and the second mold, clamp the rotor core body of the unformed rotor core between the first mold and the second mold to provide pressure along the clamping direction to the clamped rotor core body by the first mold and the second mold, and provide a fluid molding material to the magnet cavities of the unformed rotor core clamped between the first mold and the second mold, wherein the first mold and the second mold a first die is configured to receive therein the shaft protruding from the central through hole of the rotor core body relative to the rotor core body end, the first die having an internal recess or opening for receiving the shaft protruding from the central through hole of the rotor core body relative to the respective rotor core body end, and the recess or opening of the first die is dimensioned such that the shaft does not contact the first die and apply a force in the clamping direction when the rotor core is clamped between the first die and the second die, and the second die has an internal recess or opening for receiving the shaft protruding from the central through hole of the rotor core body relative to the respective rotor core body end, and the recess or opening of the second die is dimensioned such that the shaft does not contact the second die and apply a force in the clamping direction when the rotor core is clamped between the first die and the second die; inserting the unformed rotor core between the first die (110) and the second die (120) of the rotor core press molding system (100) with the first rotor core body end and the second rotor core body end facing the respective first and second dies in the open configuration of the first and second dies; closing the first and second dies from the open configuration to the closed configuration by moving the first and second dies toward each other to clamp the rotor core body of the unformed rotor core with a predetermined pressure between the first and second dies in the closed configuration; providing a fluid molding material into the magnet cavities of the rotor core body (11) of the unformed rotor core clamped between the first mold and the second mold; curing the fluid molding material within the magnet cavities to provide a molded rotor core; opening the first and second molds to an open configuration by moving the first and second molds away from each other; removing the molded rotor core from between the first die and the second die; A rotor core manufacturing method comprising:

2. 2. The rotor core manufacturing method of claim 1, wherein rotor core end caps (17) are provided at one or both of the first rotor core body end and the second rotor core body end, one or both rotor core end caps having cap openings (17.1) therein, the cap openings being associated with the magnet cavities of the rotor core body for one or both of providing fluid molding material into the magnet cavities through the respective cap openings and for allowing air to escape from the magnet cavities while filling the magnet cavities with fluid molding material.

3. The rotor core manufacturing method of claim 2 , wherein a fluid molding material is provided within the magnet cavity such that a cap opening of the one or both end caps is at least partially filled.

4. 1. A rotor core pressing system for molding permanent magnets into an unformed rotor core to provide a formed rotor core for an electric motor, comprising: An unformed rotor core (10A) comprises a shaft (16) of the electric motor (1) and a rotor core body (11) having a central through hole (15) extending along and around a longitudinal axis (A) of the rotor core body, magnet cavities (12) distributed around the longitudinal axis (A), and permanent magnets (13) inserted into the magnet cavities, wherein the shaft of the electric motor is disposed in the central through hole and the magnet cavities and the central through hole are disposed around the longitudinal axis (A). a through hole extends along the longitudinal axis between opposing first and second rotor core body ends (11.1) and (11.2) of the rotor core body, and the magnet cavities have openings (12.1) at one or both of the first and second rotor core body ends for filling the magnet cavities with a fluid molding material, and the shaft protrudes from the central through hole of the rotor core body relative to one or both of the rotor core body ends; A molded rotor core (10B) includes the rotor core body (11) having the permanent magnets fixed in the magnet cavities by hardened molding material (14) in the magnet cavities; and The rotor core pressure molding system comprises a first mold (110) and a second mold (120), the first mold (110) and the second mold (120) being configured and arranged to, in an open configuration of the first mold and the second mold, insert the unformed rotor core between the first mold and the second mold with the first rotor core body end and the second rotor core body end facing the first mold and the second mold, respectively, along a clamping direction, and to, in a closed configuration of the first mold and the second mold, clamp the rotor core body of the unformed rotor core between the first mold and the second mold to provide pressure along the clamping direction to the clamped rotor core body by the first mold and the second mold, and provide fluid molding material to the magnet cavities of the unformed rotor core clamped between the first mold and the second mold, wherein the first mold and the second mold are configured and arranged to insert the unformed rotor core between the first mold and the second mold with the first rotor core body end and the second rotor core body end facing the first mold and the second mold, respectively, along a clamping direction, and to clamp the rotor core body of the unformed rotor core between the first mold and the second mold, provide pressure along the clamping direction to the clamped rotor core body by the first mold and the second mold, and provide fluid molding material to the magnet cavities of the unformed rotor core clamped between the first mold and the second mold, the first die is configured to receive therein the shaft protruding from the central through hole of the rotor core body relative to the rotor core body end, the first die has an internal recess or opening for receiving the shaft protruding from the central through hole of the rotor core body relative to the respective rotor core body end, and the recess or opening of the first die is dimensioned such that the shaft does not come into contact with the first die and apply a force in the clamping direction when the rotor core is clamped between the first die and the second die, and the second die has an internal recess or opening for receiving the shaft protruding from the central through hole of the rotor core body relative to the respective rotor core body end, and the recess or opening of the second die is dimensioned such that the shaft does not come into contact with the second die and apply a force in the clamping direction when the rotor core is clamped between the first die and the second die. Rotor core pressure forming system.

5. 5. The rotor core manufacturing method or rotor core pressure molding system according to claim 1, wherein one or both of the first mold and the second mold include a plurality of cylinder reservoirs and a plunger associated with each of the plurality of cylinder reservoirs for providing a fluid molding material within the magnet cavity of the rotor core body of the unformed rotor core, and the cylinder reservoirs of the plurality of cylinder reservoirs are arranged around the recess or the opening to receive the shaft protruding from the central through hole of the rotor core body.

6. 5. The rotor core manufacturing method or rotor core pressure molding system according to claim 1, wherein the second mold (120) is configured to provide a fluid molding material into the magnet cavities of the rotor core body of the unformed rotor core, and the first mold (110) is in contact with the unformed rotor core (10A) to be processed and includes a replaceable part (115) configured to match the unformed rotor core (10A) to be processed, and the replaceable part (115) includes an opening (119.1) that forms at least a part of the recess (119) or the opening for receiving the shaft protruding from the central through hole of the rotor core body.

7. 5. The rotor core manufacturing method or rotor core pressure molding system according to claim 1, wherein the second mold (120) is configured to provide a fluid molding material into the magnet cavities of the rotor core body of the unformed rotor core, and the first mold (110) comprises a ventilation channel (115.1), an opening of the ventilation channel (115.1) being associated with and aligned with the magnet cavities (12) of the rotor core to allow air to escape from the magnet cavities while the fluid molding material is being introduced into the magnet cavities.

8. 7. The rotor core manufacturing method or rotor core press molding system of claim 6, wherein the first mold (110) comprises a ventilation channel (115.1), an opening of the ventilation channel (115.1) associated with and aligned with the magnet cavity (12) of the rotor core to allow air to escape from the magnet cavity while the fluid molding material is being introduced into the magnet cavity, and the ventilation channel (115.1) and an opening of the ventilation channel (115.1) are provided in the replaceable part (115).

9. 7. The rotor core manufacturing method or rotor core pressure molding system of claim 6, wherein one or both of the first mold and the second mold include a plurality of cylinder reservoirs and a plunger associated with each of the plurality of cylinder reservoirs for providing a fluid molding material into the magnet cavity of the rotor core body of the unformed rotor core, and the cylinder reservoirs of the plurality of cylinder reservoirs are positioned around the recess or the opening to receive the shaft protruding from the central through hole of the rotor core body.

10. 8. The rotor core manufacturing method or rotor core pressure molding system of claim 7, wherein one or both of the first mold and the second mold include a plurality of cylinder reservoirs and a plunger associated with each of the plurality of cylinder reservoirs for providing a fluid molding material into the magnet cavity of the rotor core body of the unformed rotor core, and the cylinder reservoirs of the plurality of cylinder reservoirs are positioned around the recess or the opening to receive the shaft protruding from the central through hole of the rotor core body.

11. 9. The rotor core manufacturing method or rotor core pressure molding system of claim 8, wherein one or both of the first mold and the second mold include a plurality of cylinder reservoirs and a plunger associated with each of the plurality of cylinder reservoirs for providing a fluid molding material into the magnet cavity of the rotor core body of the unformed rotor core, and the cylinder reservoirs of the plurality of cylinder reservoirs are positioned around the recess or the opening to receive the shaft protruding from the central through hole of the rotor core body.

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