Rotor for an electric motor, method for manufacturing a rotor, electric motor with a rotor

Abstract

The invention relates to a rotor (1) for an electric motor, comprising: at least one rotor lamination stack unit (2), wherein the rotor lamination stack unit (2) comprises: at least one cavity (3) for receiving at least one magnet unit (4), at least one magnet unit (4), wherein the at least one magnet unit (4) is arranged in the at least one cavity (3); at least one temperature sensor unit (5) for measuring a temperature of the magnet unit (4); characterized in that the temperature sensor unit (5) is arranged directly on a surface (8) of the at least one magnet unit (4); further comprising a cable (6), wherein the at least one cable (6) is connected to the temperature sensor unit (5) and wherein the at least one cable (6) extends in an axial direction (7) of the rotor lamination stack unit (2) along the at least one cavity (3).The invention further relates to a method for manufacturing such a rotor, as well as an electric motor with such a rotor.

Description

[0001] The invention relates to a rotor for an electric motor, comprising: at least one rotor lamination stack unit, wherein the rotor lamination stack unit comprises: at least one cavity for receiving at least one magnet unit, at least one magnet unit, wherein the at least one magnet unit is arranged in the at least one cavity; at least one temperature sensor unit for measuring a temperature of the magnet unit, a method for manufacturing a rotor, and an electric motor with a rotor.

[0002] Rotors for electric motors are generally known from the prior art. In permanent magnet electric motors, magnets are arranged in the rotor laminations to generate a magnetic field. The temperature of the magnets influences the performance of the electric motor during operation. For this reason, precise information about the temperature of the magnets on the rotor is of interest for the control and regulation of the electric motor during operation. However, due to the rotor's design, measuring the temperature is difficult.

[0003] From DE 10 2020 123 052 A1 a magnetic temperature information output device for a rotating electric machine is known.

[0004] A rotor for an electric machine is known from DE 10 2022 124 821 A1.

[0005] From JP2004222387A a temperature sensor for detecting the temperature of a magnet in a rotor is known.

[0006] From WO 2022 / 243812 A1 a method for estimating the temperature of a magnet of an electric machine is known.

[0007] In this context, it has become apparent that there is a need to provide a rotor for an electric motor, in particular a need to provide an improved rotor for an electric motor.

[0008] It is therefore an object of the present invention to eliminate, or at least partially eliminate, the disadvantages described above in rotors for electric motors. In particular, it is an object of the present invention to provide an improved rotor for an electric motor.

[0009] This problem is solved according to the invention in a rotor of the generic type by arranging the temperature sensor unit directly on a surface of the at least one magnet unit; further comprising a cable, wherein the at least one cable is connected to the temperature sensor unit and wherein the at least one cable extends in an axial direction of the rotor lamination stack along the at least one cavity. In particular, the problem is solved by a rotor with the features of independent claim 1.

[0010] Furthermore, the problem is solved by a method for manufacturing a rotor with the features of independent claim 6 and an electric motor with the features of independent claim 10.

[0011] Features disclosed in connection with the rotor according to the invention naturally also apply in connection with the method according to the invention, the electric motor according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, mutual reference is always made or can be made.

[0012] According to a first aspect of the present invention, a rotor for an electric motor is provided, comprising: at least one rotor lamination stack unit, wherein the rotor lamination stack unit comprises: at least one cavity for receiving at least one magnet unit, at least one magnet unit, wherein the at least one magnet unit is arranged in the at least one cavity; at least one temperature sensor unit for measuring a temperature of the magnet unit; characterized by the fact that the temperature sensor unit is arranged directly on a surface of the at least one magnet unit; further comprising a cable, wherein the at least one cable is connected to the temperature sensor unit and wherein the at least one cable extends in an axial direction of the rotor lamination stack along the at least one cavity.

[0013] The term rotor lamination stack refers to a structural component designed to guide and shape a magnetic field. The rotor lamination stack preferably comprises a plurality of rotor laminations arranged one above the other. The rotor lamination preferably comprises a silicon-steel alloy. The rotor lamination stack preferably mounts on a rotor shaft. The rotor preferably comprises a plurality of rotor lamination stacks arranged one behind the other.

[0014] In this context, the term cavity refers in particular to a hollow space designed to accommodate at least one magnetic unit. The cavity may have a geometry that corresponds at least partially to the geometry of the magnetic unit. For example, the cavity may have a geometry on one or two sides that can act as a guide for the magnetic unit. The magnetic unit can thus advantageously be inserted into the cavity. The cavity may also have a free space designed to provide room for a temperature sensor unit and at least one associated cable. The rotor lamination stack unit may preferably have a plurality of cavities with magnetic units arranged therein.

[0015] The term "temperature sensor unit" refers specifically to a sensor configured to detect the temperature of a magnet. The temperature sensor unit may include a temperature sensor based on a change in resistance. For example, the temperature sensor may include one or more of the following: platinum resistance thermometers or thermistors. The temperature sensor unit is connected to a cable. In this context, the cable is a power cable. The cable may preferably be connected to a first coil so that current can be transmitted to the temperature sensor. The cable may be connected to an interface on a rotor shaft. The first coil and the cable may preferably be arranged on the rotor or the rotor shaft. The cable may preferably be arranged within the cavity and extend in the axial longitudinal direction of the rotor to an end face of the rotor.The first coil can preferably be arranged on an end face of the rotor or an outer laminated core assembly. The first coil can preferably be configured to exchange energy and signals via induction with a second coil located in a stationary area of ​​the electric motor. The second coil can, for example, be connected to an ammeter that measures the current in the second coil and provides this information to an evaluation unit for determining the temperature of the magnet assembly. For example, the first coil is supplied with electrical power due to excitation by the second coil. The current flowing through the second coil changes depending on the electrical resistance of the temperature sensor. The electrical resistance of the temperature sensor changes depending on the temperature of the magnet assembly. The ammeter can detect this change in current.An evaluation unit can thus easily measure the temperature of the magnetic unit. Alternatively or additionally, the cable can be routed to an interface, for example, a connector in the rotor shaft, to access the temperature from there. The cable and temperature sensor unit can preferably be temperature-resistant. The cable and temperature sensor unit can preferably be pressure-resistant. For example, the cable and temperature sensor unit can be designed to withstand pressures up to 60 bar.

[0016] In this context, the term "magnetic unit" refers specifically to a permanent magnet for generating a magnetic field. The magnetic unit can be connected to the rotor lamination stack via a positive-locking connection.

[0017] The invention is based on the understanding that the temperature of rotor magnets is relevant for the control and thus the performance and efficiency of electric motors. Arranging the temperature sensors proves difficult. Previously, the rotor was manufactured using conventional methods, with holes subsequently drilled into it and the temperature sensors then positioned within these holes. This weakens the rotor lamination stack with regard to its magnetic properties. Furthermore, this method does not guarantee optimal contact between the temperature sensor and the magnet. With such a connection, there is always either a gap or a plastic insert between the magnet and the sensor, as otherwise there is a risk of damaging the magnet through the hole. Consequently, the temperature measurements are inaccurate.Furthermore, due to the spatial distance, the measurement results are also delayed when the assembly heats up. This introduces further inaccuracies. Moreover, such a connection is associated with high manufacturing costs. To overcome these disadvantages, the invention proposes arranging the temperature sensor unit directly, i.e., immediately, on a surface of the magnet unit. Furthermore, the cavity for receiving the magnet unit is designed to allow for the routing of the necessary cable for the temperature sensor unit. The cable can be routed within the cavity along the longitudinal axis of the rotor and exited at the end face. The remaining space in the cavity can then be filled, for example, with a plastic material using a transfer molding process or by pressureless resin casting, resulting in a functional rotor.In this way, an efficient, cost-effective rotor with precise temperature control can be provided.

[0018] Advantageous embodiments are claimed in the dependent claims and are explained in more detail below.

[0019] According to a preferred embodiment, the at least one temperature sensor unit can be arranged on the surface of the at least one magnetic unit using an adhesive method.

[0020] The temperature sensor unit can, for example, be glued to a surface during assembly. An adhesive can be used for this purpose. The surface can be oriented radially outwards or circumferentially to the rotor.

[0021] This allows for immediate arrangement. This can have a positive impact on measurement accuracy. This can have a positive impact on manufacturing costs. This can have a positive impact on the efficiency of the electric motor.

[0022] According to a preferred embodiment, the at least one temperature sensor unit can be connected to an inner surface of the at least one cavity via a positive-locking connection.

[0023] The positive-locking connection can be achieved in this case using a plastic or resin that is poured into the cavity.

[0024] This allows for a stable arrangement of the magnet unit, including the attached sensor unit, within the laminated core. This can have a positive effect on the efficiency of the electric motor.

[0025] According to a preferred embodiment, the at least one cavity can have a free space that is not occupied by the at least one magnet unit, the at least one sensor unit and the cable, and wherein the free space for fastening the one magnet unit, the at least one sensor unit and the cable is filled with a plastic and / or resin.

[0026] The term "free space" refers to the space not occupied by the components: the magnet unit, the sensor unit, and the cables. This free space is required, among other things, for assembly. Advantageously, after the components are assembled or installed, this free space is filled with a plastic or resin to create a positive connection between the components and the rotor lamination stack.

[0027] This allows for a stable arrangement of the magnet unit, including the attached temperature sensor unit, within the laminated core assembly. This can have a positive effect on the efficiency of the electric motor.

[0028] According to a preferred embodiment, the rotor can have at least a second rotor lamination stack unit, wherein the cable of the at least first rotor lamination stack unit is arranged along an axial direction of the second rotor lamination stack unit within a cavity of the at least one second rotor lamination stack unit.

[0029] In other words, the rotor lamination stacks are arranged one on top of the other, and the cables within them are routed through the cavities of the subsequent rotor lamination stacks. This allows access to lower-lying temperature sensor units. Preferably, the rotor lamination stacks are interlocked or twisted relative to each other. Furthermore, precise, direct connection of the sensor units is possible even with interlocked rotor lamination stacks, as no additional drilling is required. This can have a beneficial effect on accessibility.

[0030] Another aspect of the present invention relates to a method for manufacturing a rotor described in more detail above, comprising: Providing at least one rotor lamination stack unit with at least one first cavity; Provide at least one temperature sensor unit with one cable (S2); provide at least one magnet unit (S3); Bonding the temperature sensor unit to a surface of at least one magnetic unit (S4); Arrangement of the at least one magnetic unit in the at least one cavity (S5); filling a space not occupied by the at least one magnetic unit, the at least one sensor unit and the cable with a plastic (S6).

[0031] In this way, an efficient and temperature-controlled rotor can be provided.

[0032] According to a preferred embodiment, filling can be carried out via a transfer molding process.

[0033] In this way, a rotor can be manufactured in a cost-effective manner.

[0034] According to a preferred embodiment, the method can further include leading one end of the cable out of the cavity.

[0035] By bringing the sensor information out, a connection to a coil for transmitting the sensor information can be advantageously enabled.

[0036] According to a preferred embodiment, the method may further comprise: providing at least one second rotor lamination stack unit with at least one first cavity; Repeat steps S2 to S4 for at least one second rotor lamination stack unit; Arranging at least one second rotor lamination stack unit on the at least one first rotor lamination stack unit; Passing the cable of the at least first rotor lamination stack unit along an axial direction of the second rotor lamination stack unit within a cavity of the at least one second rotor lamination stack unit.

[0037] Another aspect concerns an electric motor with a rotor described in more detail above.

[0038] The invention is explained below with the aid of a drawing. The drawing shows: Fig. 1 a rotor according to the invention of a first embodiment, Fig. 2 a magnetic unit of a first embodiment, Fig. 3 a rotor according to the invention of a first embodiment, Fig. 4 a rotor according to the invention of a first embodiment.

[0039] Fig. Figure 1 describes a rotor 1 according to the invention for an electric motor. The rotor 1 comprises a laminated core unit 2. The laminated core unit 2 comprises a plurality of stacked rotor laminations. The laminated core unit 2 comprises a cavity 3. A magnet unit 4 is arranged in the cavity 3. For clarity, the magnet unit 4 is not yet completely arranged in the cavity 3. A temperature sensor unit 5 is bonded to the magnet unit 4. The temperature sensor unit 5 is bonded to a surface 8 of the magnet unit 4. A cable 6 is arranged on the temperature sensor unit 5. The cable 6 extends along an axial direction 7 of the laminated core unit 2. A rotor opening 12 for receiving a rotor shaft (not shown) is also shown.

[0040] Fig. 2 a magnetic unit 4 with a temperature sensor unit 5 and a cable 6. The temperature sensor unit 5 is arranged on a surface 8 of the magnetic unit 4.

[0041] Fig. Figure 3 shows a rotor 1 according to the invention. It can be seen that a free space 10 still exists in the cavity 3 when the magnet unit 4, temperature sensor unit 5, and cable 6 are already arranged. This free space 10 is filled, for example, by a transfer molding process. The free space 10 extends, among other things, between an inner surface 9 of the cavity 3 and the temperature sensor unit 5. The transfer molding process enables a positive-locking connection between the temperature sensor unit 5 and the rotor lamination stack unit 2.

[0042] Fig.4. A rotor 1 according to the invention. The rotor 1 comprises a first laminated core unit 2 and a further laminated core unit 11, as well as additionally further laminated core units. The laminated core units 2, 11 are arranged one behind the other. The cable 6 is routed along the cavities running in the laminated core units 2, 11. This cable is led out through the cavity to an end face of the rotor 1. There, it can be connected, for example, to a coil for signal transmission (not shown). Reference symbol list 1 Rotor 2 Rotor lamination package unit 3 Cavity 4 magnetic units 5 Temperature sensor unit 6 cables 7 axial direction 8 Surface magnetic unit 9 Inner cavity 10 Free space 11 additional rotor lamination stack units 12 Rotor opening for rotor shaft QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 123 052 A1

[0003] DE 10 2022 124 821 A1

[0004] JP 2004222387A

[0005] WO 2022 / 243812 A1

[0006]

Claims

[1] Rotor (1) for an electric motor, comprising: at least one rotor lamination stack unit (2), wherein the rotor lamination stack unit (2) comprises: at least one cavity (3) to accommodate at least one magnet unit (4), at least one magnetic unit (4), wherein the at least one magnetic unit (4) is arranged in the at least one cavity (3); at least one temperature sensor unit (5) for measuring a temperature of the magnetic unit (4); characterized by , that the temperature sensor unit (5) is arranged directly on a surface (8) of the at least one magnet unit (4); further comprising a cable (6), wherein the at least one cable (6) is connected to the temperature sensor unit (5) and wherein the at least one cable (6) extends in an axial direction (7) of the rotor lamination stack unit (2) along the at least one cavity (3). [2] Rotor (1) according to claim 1, characterized by, that the at least one temperature sensor unit (5) is arranged on the surface (8) of the at least one magnet unit (4) by means of an adhesive method. [3] Rotor (1) according to claim 1 or 2, characterized by , that the at least one temperature sensor unit (5) is connected to an inner surface (9) of the at least one cavity (3) via a positive locking connection. [4] Rotor (1) according to any one of the preceding claims, characterized by , that the at least one cavity (3) has a free space (10) which is not occupied by the at least one magnet unit (4), the at least one temperature sensor unit (5) and the cable (6), and wherein the free space (10) is filled with a plastic for fastening the at least one magnet unit (4), the at least one temperature sensor unit (5) and the cable (6). [5] Rotor (1) according to any one of the preceding claims, characterized by, that the rotor (1) has at least one second rotor lamination stack unit (11), wherein the cable (6) of the at least first rotor lamination stack unit (2) is arranged along an axial direction of the second rotor lamination stack unit (11) within a cavity of the at least one second rotor lamination stack unit (11). [6] Method for manufacturing a rotor (1) according to any one of claims 1 to 5, comprising: Providing at least one rotor lamination stack unit (2) with at least one first cavity (3); Providing at least one temperature sensor unit (5) with a cable (6) (S2); Providing at least one magnetic unit (4) (S3); Bonding the temperature sensor unit (5) to a surface (8) of the at least one magnetic unit (4) (S4); Arrangement of the at least one magnet unit (4) in the at least one cavity (3) (S5); Filling a free space (10) that is not filled by the at least one magnetic unit (4), the at least one temperature sensor unit (5) and the cable (6) with a plastic (S6). [7] Method according to claim 6, wherein the filling is carried out via a transfer molding process. [8] Method claim 6 or 7, further comprising bringing out one end of the cable (6) from the cavity (3). [9] Method according to any one of claims 6 to 8, comprising: Providing at least one second rotor lamination stack unit (11) with at least one first cavity; Repeat steps S2 to S4 for at least one second rotor lamination stack unit (11); Arranging at least one second rotor lamination stack unit (11) on top of at least one first rotor lamination stack unit (2); Passing the cable (6) of the at least first temperature sensor unit (5) of the at least first rotor lamination stack unit (2) along an axial direction of the second rotor lamination stack unit (11) within a cavity of the at least one second rotor lamination stack unit (11). [10] Electric motor with a rotor (1) according to any one of claims 1 to 5.

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