Electric motor

Abstract

The invention relates to an electric motor comprising an active subassembly that includes a stator and a rotor, and comprising an electronics subassembly. In order to provide an improved electric motor, according to the invention, the electric motor includes a shielding device that is placed between the active subassembly and the electronics subassembly, and the shielding device contains a ceramic material.

Description

[0001] Description

[0002] electric motor

[0003] The invention relates to an electric motor.

[0004] Electric motors usually comprise an active assembly of stator and rotor, which are used to generate torque.

[0005] In addition to the active module, electric motors can be equipped with a motor encoder. The motor encoder is integrated into the motor housing and is often not visible from the outside. Motor encoders can perform various functions. In many applications, the motor encoder performs a dual function:

[0006] • It provides the speed, commutation and / or position information required by the current control and / or

[0007] • serves as a position sensor for a position control system in the actuator.

[0008] The electric motor is often powered by a power converter, such as a frequency converter. The converter is the power control element that converts an input AC voltage with a fixed frequency, amplitude, and phase number into an output AC voltage with a variable frequency and amplitude and a fixed phase number. Converters can be installed remotely from the electric motor or within the motor housing.

[0009] The electric motor can thus also have a motor encoder and / or power converter as an electronic assembly in the motor housing. Within the motor housing, the electronic assembly is typically arranged in the axial direction of the rotor next to the active assembly within the motor housing. During operation of the electric motor, the thermal energy generated by the active assembly is distributed within the electric motor and thus within the motor housing. The area of ​​the electric motor containing the electronic assembly is subjected to significant heat and thermal stress by the active assembly.

[0010] The disadvantage of this is that the components of the electronic assembly must be designed for these thermal loads so that they can withstand these thermal loads during the intended operation of the electric motor.

[0011] Electronic components, such as encoders or converters, for electric motors are specified for high temperatures of, for example, 115 °C to 120 °C so that they can withstand the thermal stress during normal operation of the electric motor. Furthermore, some electric motors are limited in their performance curve to prevent the electronic components inside the electric motor from overheating.

[0012] From US 2021 / 290929 A1 an electronic module for a cardiac assist system, i.e. an implanted left ventricular assist device, is known, comprising a motor housing and an electronic part which are connected to each other by a coupling part to form a liquid-tight module housing.

[0013] From US 2015 / 171709 A1 an electric drive device for a vehicle is known, comprising an insulating element which extends parallel to the axis line of the rotating shaft of an electric motor and is provided with a resin wall in order to correct the position of the motor terminal with respect to the motor connection terminal.

[0014] US 2012 / 039729 A1 discloses a motor for use in a cooling fan with a heat-conducting insulator arranged between the cooling plate and the circuit board and resting against the cooling plate and the front face of the circuit board. JP2009261118 A discloses a motor with an encoder having a ceramic coating applied to the surface of the output-side mount facing the motor winding to prevent the transfer of heat and far-infrared rays from the motor winding to the encoder.

[0015] The invention is based on the object of providing an improved electric motor.

[0016] This object is achieved by a device according to claim 1, i.e. by an electric motor with an active assembly, which comprises a stator and a rotor, an electronic assembly and a shielding device, which is arranged between the active assembly and the electronic assembly, wherein the shielding device has a ceramic material, wherein a material proportion of the ceramic material with respect to a total material proportion of the shielding device (12) is at least 50%, preferably at least 80%, wherein the electric motor (1) has a shaft (6) and between the active assembly (2) and the electronic assembly (7) a first bearing (13) of the shaft (6) is arranged, wherein the shielding device (12) radially encloses the shaft (6) and / or the first bearing (13).

[0017] Advantageous developments of the invention are specified in the dependent claims 2 to 15.

[0018] The active module and electronic module are arranged in a common motor housing of the electric motor.

[0019] By using the ceramic material for the shielding device and by arranging the shielding device between the active module and the electronic module, the electronic module is thermally shielded from the thermal energy generated by the active module during operation of the electric motor during normal operation. By using the ceramic material for the shielding device, an effective thermal insulation layer is provided between the active module and the electronic module. Furthermore, the shielding device provides electrical and / or magnetic shielding of the electronic module from the active module.

[0020] The shielding device therefore acts as a thermal insulation layer within the electric motor and reduces the heat transfer of the thermal energy generated by the active module to the electronic module in the motor housing during operation of the electric motor.

[0021] One advantage achieved by the invention is that, during operation of the electric motor, there is reduced heat transfer from the active module to the electronic module. The electronic module of the electric motor can therefore be designed for a lower temperature, which in particular allows costs to be saved in the area of ​​the electronic module. Additionally or alternatively, a limitation of the performance curve of the electric motor, which is due to the heat input to the electronic module caused by the active module, can be eliminated, so that an electric motor with higher performance can be provided.

[0022] In an advantageous embodiment of the invention, the shielding device is designed such that the heat transfer of the thermal energy generated by the active module to the electronic module taking place in the motor housing during operation of the electric motor is reduced by the shielding device.

[0023] In an advantageous embodiment of the invention, the shielding device is designed such that, during normal operation of the electric motor, a maximum temperature of 105°C is present at the electronic assembly, whereas the area of ​​the active assembly can have a maximum temperature of 250°C, preferably a maximum of 150°C. Depending on whether the motor is synchronous or asynchronous, the maximum temperature of the active assembly can vary.

[0024] A material proportion of the ceramic material is at least 50%, preferably at least 80%, with respect to a total material proportion of the shielding device.

[0025] By using a high material proportion of the ceramic material with respect to the total material proportion of the shielding device, an improved thermal insulation layer is provided between the active assembly and the electronic assembly, so that the heat input to the electronic assembly caused by the active assembly during normal operation of the electric motor is reduced.

[0026] In a further advantageous embodiment of the invention, the shielding device consists of the ceramic material.

[0027] The ceramic shielding device thereby reduces the heat input to the electronic assembly caused by the active assembly during normal operation of the electric motor.

[0028] The electric motor has a shaft and a first bearing of the shaft is arranged between the active assembly and the electronic assembly, wherein the shielding device radially encloses the shaft and / or the first bearing.

[0029] Preferably, the shielding device is designed as a bearing shield and serves to support the shaft by means of the first bearing. Preferably, the first bearing is mechanically secured via the shielding device.

[0030] It is also conceivable for the first bearing to be mechanically fastened by means of a separate bearing shield, e.g. made of metal, and for the motor shaft to be mounted on this. In this case, the shielding device would be arranged between the separate bearing shield and the electronics assembly and would enclose the shaft in such a way that rotation of the shaft is possible. The shielding device has an opening for the shaft to pass through. It is advantageous to keep the radial gap between the shaft and the shielding device as small as possible; in particular, the gap should be less than 20 mm, preferably less than 10 mm. The shielding device hereby provides an improved thermal barrier for the electronics assembly.

[0031] It is also conceivable for the first bearing to be arranged in the region of the end shield housing section; i.e. the first bearing would be downstream of the electronics assembly and preferably mechanically fastened to the end shield housing. In this case, the shielding device would be arranged between the active assembly and the electronics assembly and would enclose the shaft in such a way that rotation of the shaft is possible. The shielding device has an opening to allow the shaft to pass through. The radial gap between the shaft and the shielding device is advantageously kept as small as possible; in particular, the gap should be less than 20 mm, preferably less than 10 mm.

[0032] The shielding device is preferably arranged in a fixed manner within the motor housing, i.e. it does not move during operation of the electric motor.

[0033] The electric motor preferably comprises a second bearing which supports the shaft on the side of the electric motor facing away from the electronic assembly (A-side).

[0034] In a further advantageous embodiment of the invention, the shielding device preferably completely covers the active module on its side surface aligned with the electronic module.

[0035] In a further advantageous embodiment of the invention, the shielding device has a disc-shaped region or is designed in a disc-shaped manner. This disc-shaped region preferably has a diameter of at least 35 mm.

[0036] If the motor is not round on the inside, it is also conceivable for the shielding device to be designed such that it is positioned against the inner housing wall of the electric motor. The shielding device therefore has a region that corresponds to the cross-section of the inwardly directed housing of the electric motor. The sectional plane of the cross-section is in particular orthogonal to the axis of the rotor and / or the shaft.

[0037] In a further advantageous embodiment of the invention, the shielding device has a first region extending substantially orthogonally to the axis of the rotor.

[0038] The axis of the rotor typically coincides with the axis of the electric motor shaft. The first region thus extends substantially orthogonally to the extended axis of the rotor and preferably also extends substantially orthogonally to the axis of the electric motor shaft.

[0039] The first region extending from the shielding device substantially orthogonal to the axis of the rotor is preferably designed such that the side surface of the electronic assembly which is aligned in the direction of the rotor and / or stator is concealed, in particular completely concealed, by the shielding device.

[0040] Preferably, the shielding device projects beyond the side surface of the electronic assembly, which is oriented toward the rotor and / or stator. The shielding device projects beyond the electronic assembly, particularly in the radial direction and / or in the longitudinal direction relative to the axis of the rotor and / or the shaft of the electric motor. The first region is preferably at least 10 mm, preferably at least 20 mm, long.

[0041] Preferably the first area is not longer than 280 mm.

[0042] Essentially orthogonal to the axis of the rotor means in particular an alignment of the first region of the shielding device to the axis of the rotor with a deviation of ± ( plus or minus ) 20 ° , preferably ± ( plus or minus ) 10 ° , from a perpendicular to the axis of the rotor .

[0043] In a further advantageous embodiment of the invention, the first region extending from the shielding device substantially orthogonal to the axis of the rotor, such as the disk-shaped region, preferably has only one opening for the shaft and / or the first bearing and / or a cable feedthrough for supplying energy to the active assembly.

[0044] In a further advantageous embodiment of the invention, the shielding device is guided to the inside of the motor housing.

[0045] In a further advantageous embodiment of the invention, the shielding device has a second region extending substantially parallel to the axis of the rotor, which radially surrounds at least 30%, preferably completely, of the electronic assembly.

[0046] The electronic assembly is surrounded by the shielding device on the side surface facing the motor housing to at least 30%, preferably completely.

[0047] Essentially parallel to the axis of the rotor means in particular an alignment of the second region of the shielding device to the axis of the rotor with a deviation of ± (plus or minus) 20 °, preferably ± (plus or minus) 10 °, to a parallel to the axis of the rotor and / or the shaft of the electric motor.

[0048] Preferably, the region extending from the shielding device substantially orthogonally to the rotor axis has a collar that at least partially, preferably completely, radially surrounds the electronic assembly. The collar extends in particular in the direction of the end shield housing section of the electric motor. This collar is preferably radially formed.

[0049] Preferably, the second region is aligned parallel to the extended axis of the rotor.

[0050] The second region of the shielding device can be formed integrally with the first region of the shielding device. It is also conceivable for the second region of the shielding device or a part of the second region of the shielding device to be formed as a separate component detached from the first region of the shielding device. In this case, it is advantageous, for example, if the second region of the shielding device or the part of the second region of the shielding device is connected to the end shield housing section of the electric motor and from there is guided via the electronics assembly. The second region of the shielding device is preferably brought directly up to the first region of the shielding device, so that in particular the second region of the shielding device and the first region of the shielding device are directly adjacent to one another and / or are in a mechanically operative connection.

[0051] In a further advantageous embodiment of the invention, the wall thickness of the shielding device in the first region is greater than the wall thickness of the shielding device in the second region. Preferably, the wall thickness of the shielding device in the first region is at least 15% thicker than the wall thickness of the shielding device in the second region. The wall thickness of the shielding device in the first region is preferably at least 1 mm.

[0052] In a further advantageous embodiment of the invention, the electric motor has a motor housing, wherein the motor housing has a stator housing section which surrounds the stator, and a separately formed electronic assembly housing section which surrounds the electronic assembly.

[0053] The stator housing section is, in particular, the housing section of the motor that surrounds the stator on its radial outer surface. The stator housing section, in particular, forms part of the longitudinal side of the electric motor.

[0054] The stator housing section can be formed as a separate motor housing. However, it is also conceivable for part or all of the stator housing section of the motor housing to be formed directly by the stator itself.

[0055] Preferably, the stator housing section of the motor housing is metallic.

[0056] Preferably, a large part of the heat generated by the active assembly during operation of the electric motor is dissipated via the motor housing of the stator housing section.

[0057] Preferably, the shielding device is positioned at the interior of the electronic assembly housing section. However, it is also conceivable for the shielding device to form part of the electronic assembly housing section.

[0058] In an advantageous embodiment of the invention, the stator housing section and the electronics assembly housing section have essentially the same cross-section. The electronics assembly housing section preferably forms the axial extension of the motor housing over the electronics assembly.

[0059] In an advantageous embodiment of the invention, the motor housing is closed at the front in the area of ​​the electronic assembly by means of a separate end shield housing section.

[0060] In an advantageous embodiment of the invention, the electric motor does not have an active cooling device, such as a fan.

[0061] In a further advantageous embodiment of the invention, the electronics assembly housing section of the motor housing, which adjoins the stator housing section, is made of metal.

[0062] The electronic assembly housing section is preferably metallic from the area adjacent to the stator housing section over the entire radial area of ​​the electronic assembly housing section, preferably up to the end shield housing section.

[0063] The stator housing section is preferably in direct mechanical connection with the electronic assembly housing section.

[0064] Preferably, the end shield housing section is made of metal.

[0065] It is also conceivable for only part or sections of the electronics assembly housing section to be made of metal. The area that supplies the electric motor's power can be made of plastic, for example. The metal electronics assembly housing section improves heat dissipation of the thermal energy generated by the active assembly during operation of the electric motor.

[0066] In a further advantageous embodiment of the invention, the electronic components are additionally thermally shielded by the shielding device from the metallic region of the electronic component housing section of the motor housing, which serves to transport the heat of the energy generated by the active component, in the interior of the motor housing.

[0067] The heat generated by the active module during operation is dissipated from the active module via the metallic motor housing. The shielding device shields the electronic modules from the heat generated by the metallic motor housing.

[0068] In a further advantageous embodiment of the invention, the stator housing section and / or electronic assembly housing section has cooling fins.

[0069] In a further advantageous embodiment of the invention, the shielding device spatially separates the interior of the motor housing of the electric motor between the active module and the electronic module.

[0070] In this case, the shielding device preferably has only one opening for the passage of the cables for the power supply of the active module.

[0071] If the shielding device supports the first bearing, the shielding device extends from the outside of the first bearing to the inside of the motor housing.

[0072] If the shielding device is arranged directly around the shaft, it extends from the shaft to the inside of the motor housing. For this purpose, the shielding device can be disk-shaped, for example.

[0073] The shielding device can be routed to the inside of the motor housing. However, it is also conceivable for the shielding device to be spaced from the inside of the motor housing.

[0074] In a further advantageous embodiment of the invention, the shielding device covers the side surface of the electronic assembly that is aligned with the stator and / or rotor. This improves the thermal shielding of the electronic assembly from the active assembly.

[0075] Preferably, the side surface of the active assembly facing the electronic assembly is completely covered by the shielding device.

[0076] In a further advantageous embodiment of the invention, a metallic bearing shield is arranged between the shielding device and the active assembly.

[0077] The bearing shield is preferably connected to the electronics assembly housing section or is part of the electronics assembly housing section.

[0078] The bearing shield is preferably used to support the first bearing of the shaft.

[0079] The heat generated by the active assembly can be conducted via the metallic bearing shield into the outer part of the electronic assembly housing section, so that there is optimized heat transfer.

[0080] In a further advantageous embodiment of the invention, the electronic assembly is radially surrounded by the shielding device. The shielding device thus has a side surface facing the active assembly and also a side surface oriented in the direction of the extended axis of the rotor.

[0081] The outer area of ​​the electronic assembly, which is adjacent to the motor housing, is thermally shielded from the motor housing.

[0082] For a round electric motor housing, the shielding device can be pot-shaped, for example. The pot-shaped shielding device thermally shields the electronics assembly from the stator and the motor housing.

[0083] In a further advantageous embodiment of the invention, the electronic assembly is a power converter, in particular a converter, and / or a motor encoder.

[0084] The motor encoder is designed in such a way that it supplies the speed, commutation and / or position information required by the current control and / or serves as a position encoder for a position control present in the actuator.

[0085] Power converters include converters, rectifiers, inverters and DC-DC converters.

[0086] The converter generates a new alternating voltage from an alternating voltage that differs in frequency and amplitude.

[0087] The converter is in particular a power actuator that converts an input alternating voltage with a fixed frequency, amplitude and number of phases into an output alternating voltage with variable frequency and / or amplitude and a fixed number of phases.

[0088] In a further advantageous embodiment of the invention, the ceramic material comprises aluminum oxide (Al2O3), zirconium oxide (ZrCt) and / or silicon nitride (SiA1A). Aluminum oxide, zirconium oxide and / or silicon nitride enable a similar rigidity of the component compared to steel with a lower weight and a lower thermal conductivity.

[0089] In a further advantageous embodiment of the invention, the shielding device has a structure, wherein the structure is such that at least one cavity is at least partially surrounded by material.

[0090] In a further advantageous embodiment of the invention, the structure is such that a plurality of cavities are at least partially enclosed by material.

[0091] The structure may be a honeycomb structure. The structure may be a lattice structure.

[0092] An embodiment is advantageous in which the cavity is completely enclosed by material.

[0093] An embodiment is advantageous according to which the cavity is at least partially filled with a material having a thermal conductivity of less than 1 W / (m-K).

[0094] In a further advantageous embodiment of the invention, the shielding device has a wall thickness of 0.5 mm to 25 mm.

[0095] The thickness of the shielding device can provide improved thermal shielding of the electronic assembly from the active assembly.

[0096] In a further advantageous embodiment of the invention, the shielding device is formed in one piece.

[0097] In a further advantageous embodiment of the invention, the shielding device has a closed surface structure and has only one opening for the first bearing, which is mechanically connected to the shielding device, and / or an opening for carrying out the energy supply for the active module.

[0098] In an advantageous embodiment of the invention, the power range of the electric motor for intended operation is between 50W and 630kW.

[0099] In an advantageous embodiment of the invention, the electric motor has an axle height which is between 20 mm and 280 mm.

[0100] In an advantageous embodiment of the invention, the electric motor is designed such that it can be used as a feed axis, handling axis, auxiliary axis, general drive axis, main spindle and / or secondary spindle.

[0101] In an advantageous embodiment of the invention, the shielding device is designed such that the electronic module is thermally shielded from the active module. Thermal shielding means, in particular, that a temperature gradient of approximately 58% is achieved between the active module and the electronic module during proper operation of the electric motor.

[0102] In an advantageous embodiment of the invention, a motor brake for braking the motor is arranged in the motor housing between the active module and the electronic module. The shielding device is preferably arranged between the motor brake and the electronic module.

[0103] In the following, the invention and embodiments of the invention are described and explained in more detail with reference to the exemplary embodiments shown in the figures. They show:

[0104] FIG 1 is a schematic representation of an electric motor from the prior art, FIG 2 is a schematic representation of an electric motor in an embodiment according to the invention, and

[0105] FIG 3 is a schematic representation of an electric motor in an alternative embodiment according to the invention.

[0106] Elements of Figures 1 to 3 are provided with the same reference numerals as the corresponding elements of the respective figures. The electric motors are shown schematically in section.

[0107] FIG. 1 shows a schematic representation of a prior art electric motor 1. The electric motor 1 is shown in section through the longitudinal axis of the electric motor 1. The electric motor 1 comprises, in its motor housing 8, a shaft 6, a rotor 4, a stator 3, and an encoder as an electronic assembly 7.

[0108] The shaft 6 of the electric motor 1 protrudes from the A-side of the motor housing 8 .

[0109] The stator 3 is the fixed, immovable part of the electric motor 1 and is usually made of sheet steel.

[0110] The rotor 4 is the rotating part of the electric motor 1. Because the rotor 4 is mechanically firmly connected to the shaft 6, the shaft 6 is driven via the rotor 4.

[0111] The rotor 4 has a longitudinal axis 5 which coincides with the longitudinal axis of the shaft 6.

[0112] During operation of the electric motor 1, the active assembly 2, which includes the stator 3 and rotor 4, becomes extremely hot. This thermal energy is distributed within the motor housing 8, so the electronic assembly 7 must be designed to withstand the resulting thermal load. During operation of the electric motor 1, temperatures of 150 to 250°C can arise at the active assembly 2, so the electronic assembly 7, in this case the encoder, must also be designed for this temperature range.

[0113] FIG 2 shows a schematic representation of an electromor 1 in an embodiment according to the invention.

[0114] Here, the electric motor 1 is shown in a section through the longitudinal axis of the electric motor 1, analogous to Figure 1. The electric motor 1 comprises, in its motor housing 8, a shaft 6, a rotor 4, a stator 3, and an encoder as an electronic assembly 7.

[0115] The shaft 6 of the electric motor 1 protrudes from the motor housing 8 on the A side.

[0116] The stator 3 is the stationary, immovable part of the electric motor 1. The rotor 4 is the rotating part of the electric motor 1. Because the rotor 4 is mechanically firmly connected to the shaft 6, the shaft 6 is driven via the rotor 4.

[0117] The rotor 4 has an axis (longitudinal axis) 5 which coincides with the longitudinal axis of the shaft 6.

[0118] During operation of the electric motor 1, the active assembly 2, which includes the stator 3 and rotor 4, becomes very hot.

[0119] The motor housing 8 has a stator housing section 9, which surrounds the stator 3, an electronics assembly housing section 10, which surrounds the electronics assembly 7, here the encoder, and an end shield housing section 11, which closes off the motor housing 8 on the B-side. The housing sections 9, 10, 11 are each formed separately.

[0120] It is also conceivable that the separately formed B-side end plate housing 18 of the end plate housing section 11 is formed in one piece with the electronic assembly housing 19 of the electronic assembly housing section 10.

[0121] It is also conceivable that the stator 3 itself forms the stator housing 20 of the stator housing section 9 or at least forms part of the stator housing section 9.

[0122] According to the invention, the electric motor 1 comprises a shielding device 12, which is arranged between the active module 2 and the electronic module 7. This shielding device 7 comprises a ceramic material. In the present exemplary embodiment, the shielding device 7 consists of the ceramic material silicon nitride (SiNa).

[0123] The electric motor 1 further comprises a first bearing 13 and a second bearing 14. The shaft 6 is rotatably supported by the first and second bearings 13, 14.

[0124] The first bearing 13 is mechanically fixed within the electric motor by the shielding device 12. The shielding device 12 radially surrounds the first bearing 13 and extends to the inside of the motor housing 8. The side surface oriented from the electronic assembly unit toward the rotor 4 is completely covered by the shielding device 12.

[0125] Because the interior of the motor housing 8 is round, the shielding device 12 is disk-shaped. To supply power to the stator 3, the shielding device 12 has an opening (not shown) through which the corresponding cable is routed from the electronics assembly housing section 10 to the stator housing section 9.

[0126] The shielding device 12 thus spatially separates the interior of the motor housing 8 of the electric motor 1 between the active assembly 2 and the electronic assembly 7. The shielding device 12 has a wall thickness of 10 mm. During operation of the electric motor 1, the active assembly 2 becomes extremely hot, so that the thermal energy generated by the active assembly 2 creates a thermal load and thus an increased temperature within the electric motor 1. This thermal energy is dissipated to the environment, in particular via the metallic stator housing 20 of the stator housing section 9.

[0127] Through the use of the ceramic material, the shielding device 12 forms an improved thermal insulation layer between the active module 2 and the electronic module 7, so that during normal operation of the electric motor 1, there is a reduced thermal energy input to the electronic module 7, the thermal energy generated by the active module 2. During operation of the electric motor 1, the electronic module 7 is thermally shielded by the shielding device 12 from the temperature generated by the active module 2 during operation of the electric motor 1. One advantage achieved by the invention is that during operation of the electric motor 1, there is little heat transfer from the active module 2 to the electronic module 7.The electronic assembly 7 of the electric motor 1 can consequently be designed for a lower temperature range and / or an unnecessary limitation of the power characteristic of the electric motor 1 can be omitted, so that an electric motor 1 with a higher power can be provided.

[0128] The stator housing section 9 and the electronics assembly housing section 10 are made of metal, allowing for improved and targeted heat transfer of the heat generated by the active assembly 2 during operation to the exterior of the housing and, via this, to the electric motor environment. For improved cooling, the electric motor 1 can also have cooling fins in the metal-constructed area of ​​the stator housing 20 and / or the electronics assembly housing 19.

[0129] Mechanical fastening The electronic assembly housing 19 is mechanically connected to the stator housing 20 .

[0130] The shielding device 12 is mechanically connected to the stator. It is also conceivable that the shielding device is mechanically connected to the stator housing 20 or the electronic assembly housing 19.

[0131] FIG. 3 shows a schematic representation of an electric motor 1 in an alternative embodiment according to the invention. Here, the electric motor 1 is shown in a section through the longitudinal axis of the electric motor 1, analogous to FIG. 2. This electric motor 1 differs from the electric motor 1 shown in FIG. 2 only in the described modified design of the active assembly 12 and in an additional metallic bearing plate 17, which is arranged between the active assembly 2 and the shielding device 12.

[0132] The bearing shield 17 is disk-shaped, encloses the shaft 6 radially and is guided as far as the inside of the electronics assembly housing 19. The bearing shield 17 is mechanically connected to the electronics assembly housing 19 in such a way that a targeted heat transfer of the thermal energy present at the bearing shield 17 during operation of the electric motor 1, caused by the active assembly 2, into the motor housing 8, in particular the electronics assembly housing 19, takes place. The bearing shield 17 serves the targeted and improved heat dissipation of the heat generated by the active assembly 2 during operation of the electric motor 1 into the metallic area of ​​the electronics assembly housing 19.

[0133] The shielding device 12 of Figure 3 has a first region 15 of the shielding device 12 and a second region 16 of the shielding device 12.

[0134] The first region 15 of the shielding device 12 encloses the first bearing 13 and extends from the first bearing 13 orthogonally to the axis 5 of the rotor 4 in the direction of the inside of the electronic assembly housing 19.

[0135] By means of the first region 15 of the shielding device 12, the side surface of the electronic assembly 7, which is aligned in the direction of the rotor 4, is completely covered by the shielding device 12.

[0136] The second region 16 of the shielding device 12 extends parallel to the axis 5 of the rotor 4, starting from the outer end of the first region 15 of the shielding device 12 in the direction of the end shield housing 18.

[0137] By means of the second region 16 of the shielding device 12, the side surface of the electronic assembly 7, which is oriented in the direction of the electronic assembly housing 19, is completely covered by the shielding device 12.

[0138] The wall thickness of the first region 15 of the shielding device 12 is preferably thicker than the wall thickness of the second region 16 of the shielding device 12.

[0139] The pot-shaped form of the shielding device 12 provides improved shielding of the electronic assembly 7 from the thermal energy generated by the active assembly 2 during operation of the electric motor. The first region 15 thermally shields the electronic assembly 7, in particular from the active assembly 2 and the bearing plate 17. The second region 16 of the shielding device 12 shields the electronic assembly 7, in particular from the metallic region of the electronic assembly housing 19, since this region is subject to increased heat input by the active assembly 2.

[0140] The above description is intended solely to explain the present invention. The scope of the present invention, however, is to be determined solely by the appended claims.

Claims

Patent claims 1. Electric motor (1) with an active assembly (2) which comprises a stator (3) and a rotor (4), an electronic assembly (7) and a shielding device (12) which is arranged between the active assembly (2) and the electronic assembly (7), wherein the shielding device (12) comprises a ceramic material, wherein a material proportion of the ceramic material with respect to a total material proportion of the shielding device (12) is at least 50%, preferably at least 80%, wherein the electric motor (1) has a shaft (6) and a first bearing (13) of the shaft (6) is arranged between the active assembly (2) and the electronic assembly (7), wherein the shielding device (12) radially encloses the shaft (6) and / or the first bearing (13).

2. Electric motor (1) according to claim 1, wherein the power range of the electric motor (1) for intended operation is between 50W and 630kW.

3. Electric motor (1) according to one of the preceding claims, wherein the shielding device (12) consists of the ceramic material.

4. Electric motor (1) according to one of the preceding claims, wherein the electric motor (1) has an axle height which is between 20 mm and 280 mm 5. Electric motor (1) according to one of the preceding claims, wherein the shielding device (12) has a first region (15) extending substantially orthogonally to the axis (5) of the rotor (4).

6. Electric motor (1) according to one of the preceding claims, wherein the shielding device (12) has a second region (16) extending substantially parallel to the axis of the rotor (4) and radially surrounding at least 30%, preferably completely, of the electronic assembly (7).

7. Electric motor (1) according to claim 5 and 6, wherein the wall thickness of the shielding device (12) in the first region (15) is greater than the wall thickness of the shielding device (12) in the second region (16).

8. Electric motor (1) according to one of the preceding claims, wherein the electric motor (1) has a motor housing (8), wherein the motor housing (8) has a stator housing section (9) which surrounds the stator (9), and a separately formed electronic assembly housing section (10) which surrounds the electronic assembly (7).

9. Electric motor (1) according to claim 8, wherein the electronics assembly housing section (10) of the motor housing (8), which adjoins the stator housing section (9), is made of metal.

10. Electric motor (1) according to one of the preceding claims, wherein the shielding device (12) spatially separates the interior of the motor housing (8) of the electric motor (1) between the active assembly (2) and the electronic assembly (7).

11. Electric motor (1) according to one of the preceding claims, wherein a bearing plate (17), in particular a metallic bearing plate (17), is arranged between the shielding device (12) and the active assembly (2).

12. Electric motor (1) according to one of the preceding claims, wherein the electronic assembly (7) is radially surrounded by the shielding device (12).

13. Electric motor (1) according to one of the preceding claims, wherein the electronic assembly (7) is a power converter, in particular a converter, and / or a motor encoder.

14. Electric motor (1) according to one of the preceding claims, wherein the ceramic material comprises aluminum oxide (Al2O3), zirconium oxide (ZrCt) and / or silicon nitride (Si3N4).

15. Electric motor (1) according to one of the preceding claims, wherein the shielding device (12) has a wall thickness of 0.5 mm to 25 mm.

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