Method for manufacturing a rotor for an electric motor

Abstract

The invention relates to a method for manufacturing a rotor (1) for an electric motor (2) comprising a laminated core (4) arranged on a rotor shaft (3), comprising: arranging at least two laminated cores (4) rotated relative to one another in a circumferential direction (5) on the rotor shaft (3), each having magnet pockets (6) and magnets (7) arranged in the magnet pockets (6); arranging at least one perforated disk (9) with at least one opening (10) between the two laminated cores (4) in the axial direction (8) such that the opening (10) overlaps the two magnet pockets (6) of the two laminated cores (4) in contact with the perforated disk (9) and connects the two magnet pockets (6); filling the intermediate space between the magnet pockets (6) and the magnets (7) with a hardening sealing material (11) which flows through the opening (10).

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a rotor for an electric motor, the rotor comprising a laminated core arranged on a rotor shaft. The invention further relates to a rotor manufactured by this method and to an electric motor comprising such a rotor.

[0002] From DE 10 2017214309 A1, a rotor for an electric machine is known, which comprises at least one laminated core with a number of magnet pockets arranged one behind the other in the axial direction of the rotor, in which magnets are accommodated and fixed in the magnet pockets by means of a hardened sealing material. In this document, the magnet pockets are fluidly connected to one another via at least one distribution system formed in the laminated core, which distribution system has at least one fluid passage per magnet pocket that is fluidly connected to the respective magnet pocket. The distribution system has at least one distribution passage common to these filling passages and fluidly connected to the distribution system, and the hardened sealing material runs through this distribution system continuously from magnet pocket to magnet pocket, thereby fixing the rotor.

[0003] For the fixation of the magnets in the magnet pockets of the rotor and for improving the thermal coupling of the magnets to the laminated cores of the rotor, a hardenable sealing material is often used which is injected into the magnet pockets of the rotor. This sealing material flows through the entire rotor consisting of individual laminated cores (stacks), which are rotated relative to one another due to the torque of the triplet. To be able to flow through the entire rotor, a correspondingly large cross-sectional overlap of the individual magnet pockets is required, taking into account the so-called skew angle, which also results in correspondingly large magnet pockets, which are also undesirable since they reduce the torque density of the entire electric motor.

[0004] It is therefore an object of the present invention to provide a method for producing a rotor, which makes it possible to overcome the disadvantages known from the prior art.

[0005] The above-mentioned problem is solved according to the invention by the subject matter of the independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0006] The invention is based on the general idea of ​​providing a through-hole in the laminated core arranged on the rotor shaft, which is substantially continuous in the axial direction, through which a sealing material, for example an epoxy resin, can be pressed from one end face to the other end face, thereby fixing the rotor and the magnets located in the magnet pockets of the rotor. In a method according to the invention for manufacturing a rotor for an electric motor with a laminated core arranged on the rotor shaft, at least two laminated cores rotated relative to each other in the circumferential direction, with magnet pockets and magnets arranged in the magnet pockets, are arranged on the rotor shaft, and at least one perforated disk with at least one opening is arranged between the two laminated cores in the axial direction, such that the opening connects the two magnet pockets of the two laminated cores facing each other against the perforated disk. Thus, the magnet pockets of the first laminated core overlap the openings in the perforated disk, which in turn overlap the magnet pockets of the second laminated core. The intermediate spaces between the magnet pockets and the magnets are then filled with a sealing material, for example an epoxy resin, which flows through the openings and is preferably pressed from one end face of the rotor through the openings in the magnet pockets or the perforated disk to the other end face of the rotor. This allows the individual magnet pockets to be made small enough, which ensures a relatively high torque density of the electric motor. Furthermore, improved thermal coupling of the magnets to the corresponding laminated cores is possible.

[0007] Preferably, epoxy resin is used as the sealing material, which on the one hand is able to hold each magnet in its magnet pocket and, in the hardened state, also prevents the individual laminated cores from rotating relative to each other or relative to the perforated disk, where epoxy resin is a good thermal conductor and at the same time electrically insulating.

[0008] In an advantageous development of the method according to the invention, the perforated disks are produced from individual sheet metal disks. The sheet metal disks for producing the perforated disks can be made of the same material as the sheet metal disks for the laminated core. In particular, sheet metal disks with an axial thickness d of about 0.2 mm can be used here, which allows particularly fine adjustment of the axial extension of the perforated disks. The torque density of the electric motor can be increased by using magnetic steel not only for the laminated core but also for the perforated disks.

[0009] In a further advantageous embodiment of the method according to the invention, a web extends through at least one opening in the perforated disk, which fixes two adjacent magnets in the axial direction. The openings in the perforated disk are essentially used as through-openings for the sealing material, and the web across the openings also results in an axial fixation of the two magnets in contact with each perforated disk in their magnet pockets. Such a web across the opening or a transverse web serves to reinforce the perforated disk and thus to increase its rigidity, which improves its handling. Furthermore, the amount of sealing material required can be reduced via such a web. It is self-evident here that the web across the opening does not have to cross the opening completely, but can simply be formed as a cantilever arm that protrudes into the opening. An axial fixation of two adjacent magnets is already obtained by such a cantilever arm.

[0010] Preferably, at least one magnet is form-fittingly inserted into the corresponding magnet pocket. In order to be able to achieve the highest possible torque density of the overall electric motor, it is desirable to fill the magnet pocket as completely as possible with magnets. Furthermore, due to the form-fitting connection between the magnet and the corresponding magnet pocket, the fixation of each magnet in the magnet pocket can already be achieved without the use of a sealing material.

[0011] The invention is further based on the general idea of ​​producing a rotor for an electric motor according to the method described in the preceding paragraph, which rotor is distinguished by a high torque density and thus by a high power output as well as by a secure fastening of the individual laminated cores to one another.

[0012] The invention is further based on the general idea of ​​equipping an electric motor with such a rotor, so that the advantages explained for the rotor can also be transferred to the electric motor.

[0013] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the corresponding illustrations based on the drawings.

[0014] It is obvious that the features mentioned above and those to be described below can be used not only in the respective mentioned combinations but also in other combinations or alone, without departing from the scope of the invention.

[0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention are illustrated in the drawings and will be described in detail in the following specification, in which the same reference numerals refer to the same or similar components or components having the same function. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic cross-sectional view of a rotor manufactured according to the method according to the invention; [Diagram 2] FIG. 2 is a schematic view of a portion of a perforated disk in the region of an opening with a channel of sealing material. [Diagram 3] FIG. 2 is a schematic end view of a laminated core with magnets disposed within magnet pockets of the laminated core and a perforated disk. [Figure 4] FIG. 2 is a schematic diagram showing a portion of a perforated disk.

[0017] According to FIG. 1, a rotor 1 according to the invention for an electric motor 2 has laminated cores 4 arranged on a rotor shaft 3, which are rotated relative to one another in the circumferential direction in order to be able to achieve a high torque density. Each of these laminated cores 4 has magnet pockets 6 (see also FIG. 4), in which corresponding magnets 7 are arranged. In the axial direction 8, between two adjacent laminated cores 4, a perforated disk 9 (see also FIGS. 2 to 4) with at least one opening 10 is arranged according to the invention, which is arranged between the two laminated cores 4 in such a way that the opening 10 of the perforated disk 9 connects two adjacent magnet pockets 6 with one another. Thereby, the opening 10 overlaps, for example, with the magnet pocket 6 of the laminated core 4 arranged to the right of the respective perforated disk 9 and with the magnet pocket 6 of the laminated core 4 arranged to the left of the respective perforated disk 9 with respect to FIG. 1. In order to be able to achieve a stable connection between the individual laminated cores 4, despite the magnet pockets 6 of the individual laminated cores 4 being rotated in the circumferential direction, the intermediate spaces between the individual magnet pockets 6 and the magnets 7 arranged therein are sealed with a sealing material 11, for example an epoxy resin, which is for example pressed into the intermediate spaces at point 12 (see FIG. 1 ) until it flows out again at point 13 on the opposite side of the rotor 1. The individual openings 10 are therefore through-passages for the sealing material 11.

[0018] Furthermore, the perforated disk 9 (see FIG. 2) may be made from individual sheet metal disks 14, which are preferably made from the same material as the laminated core 4, for example from magnetic steel sheet, where the thickness d of each sheet metal disk 14 may be, for example, 0.2 mm.

[0019] Furthermore, through at least one of these openings 10, a web 15 may extend, either completely across each opening 10 (see FIG. 4) and connecting the opposing faces of the openings 10 to one another or simply engaging within the openings 10 in the manner of a cantilever arm 16 (see FIG. 2). Such a web 15 or cantilever arm 16 is in this case an axial fixation for the magnets 7 arranged in two axially adjacent magnet pockets 6.

[0020] Here, at least one of these magnets 7 can be form-fittingly inserted into the corresponding magnet pocket 6, which reduces the intermediate space that has to be filled with sealing material 11, thereby increasing the torque density or power density of the electric motor 2.

[0021] In particular, a secure fixation of the individual laminated cores 4 to one another can be ensured by the perforated disks 9 provided.

[0022] 3, it can be seen that, during sealing of the intermediate space, the sealing material 11 first flows through the first magnet pocket 6a and through the openings 10 in the perforated disk 9 into the second magnet pocket 6b, thereby fixing the laminated cores 4 arranged respectively adjacent to the perforated disk 9 to the perforated disk 9. In FIG. 3, for the sake of clarity, the laminated cores 4 are not shown.

Claims

1. A method for manufacturing a rotor (1) of an electric motor (2), comprising a laminated core (4) arranged on a rotor shaft (3), at least two laminated cores (4) which are relatively rotated in the circumferential direction (5), the laminated core (4) comprising a magnet pocket (6) and a magnet (7) arranged in the magnet pocket (6), are arranged on the rotor shaft (3), in the axial direction (8), at least one perforated disk (9) having at least one opening (10) is arranged between two laminated cores (4), the opening (10) overlapping two magnet pockets (6) of the two laminated cores (4) in contact with the perforated disk (9), and is arranged to connect the two magnet pockets (6), filling the intermediate space between the magnet pocket (6) and the magnet (7) with a curable sealing material (11) flowing through the opening (10), method.

2. Using an epoxy resin as the sealing material (11), The method according to claim 1.

3. Manufacturing the perforated disk (9) from individual thin plate disks (14), The method according to claim 1 or 2.

4. Using a thin plate disk (14) having a thickness d of about 0.2 mm, The method according to claim 3.

5. At least one web (15) or cantilever arm (16) for fixing two adjacent magnets (7) in the axial direction (8) extends through at least one opening (10), The method according to claim 1 or 2.

6. Inserting at least one magnet (7) into the corresponding magnet pocket (6) in a form-fitting manner, The method according to claim 1 or 2.

7. A rotor (1) for an electric motor (2) manufactured according to the method according to claim 1 or 2.

8. An electric motor (2) comprising the rotor (1) according to claim 7. ​

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