Motor

Abstract

The invention relates to an electric machine having a rotor shaft, a floating bearing and a bearing cover, the floating bearing being provided for rotatably supporting the rotor shaft, the floating bearing having an inner ring and an outer ring, the outer ring of the floating bearing being received in a bearing receptacle formed in the bearing cover, the inner ring being fitted onto the rotor shaft, and the bearing cover being provided for the bearing cover. The bearing receptacle is designed to be interrupted by openings, the openings being spaced apart from each other in the circumferential direction.

Description

Technical Field

[0001] The present invention relates to an electric motor. Background Art

[0002] As is well known, at least two bearings, in particular rolling bearings, are used to support a shaft.

[0003] As the closest prior art, an electric motor is known from DE 10 2008 028 607 A1.

[0004] A floating bearing device is known from DE 10 2021 205 788 A1.

[0005] An electric motor is known from DE 20 2007 009 954 U1.

[0006] An electric motor is known from DE 10 2011 119 603 A1.

[0007] A torsional vibration damper with friction coefficient adjustment is known from DE 10 2020 120 389 A1.

[0008] An electric motor with a blower housing, a rotor shaft rotatably supported relative to the blower housing, and an angle sensor is known from DE 10 2020 006 831 A1.

[0009] A friction braking body for a friction brake of a motor vehicle is known from DE 10 2019 207 290 A1.

[0010] A sliding surface iron-containing layer applied by thermal spraying is known from EP 1 711 642 B1.

[0011] A controlled powder cladding welding process is known from DE 10 2018 130 798 A1.

[0012] A bearing device is known from DE 10 2016 223 009 A1. Summary of the Invention

[0013] Therefore, the object of the present invention is to improve an electric motor, wherein the operation of the electric motor should be made as safe as possible.

[0014] According to the present invention, this object is achieved by an electric motor having the features given in claim 1.

[0015] In the electric motor, an important feature of the present invention is that the electric motor has a rotor shaft, a floating bearing, and a bearing cover.

[0016] Among them, the floating bearing is arranged to rotatably support the rotor shaft.

[0017] Among them, the floating bearing has an inner ring and an outer ring. In particular, rolling elements are arranged between the inner ring and the outer ring.

[0018] Among them, the outer ring of the floating bearing is received in a bearing receiving portion which is formed, in particular molded, in the bearing cover. The bearing receiving portion is in particular a pot-shaped bearing receiving portion and / or a blind hole.

[0019] Among them, the inner ring is sleeved on the rotor shaft.

[0020] Among them, the bearing receiving portion is designed to be interrupted by an opening.

[0021] Among them, the openings are spaced apart from each other in the circumferential direction, in particular regularly spaced apart from each other.

[0022] In particular, among them, the circumferential direction is based on the rotational axis of the rotor shaft.

[0023] Therefore, according to the present invention, the bearing receiving portion of the floating bearing is designed to have an opening.

[0024] The advantage here is that the bearing receiving portion has higher elasticity, and thus the outer ring of the floating bearing can be received in the bearing receiving portion in an interference fit manner, so that slipping or co-rotation of the outer ring can be prevented, and a low static friction force can still be achieved when the outer ring moves in the axial direction. Therefore, co-rotation of the outer ring is prevented, and axial movement can be achieved with low force consumption.

[0025] Therefore, in the present invention, it is advantageous that operational safety can be achieved because co-rotation or slipping of the outer ring of the floating bearing is prevented. On the one hand, the outer ring of the floating bearing is arranged to be axially movable so as to withstand the thermally induced axial length change of the rotor shaft, but on the other hand, by connecting the outer ring to the bearing receiving portion of the bearing cover in a non-rotatable manner, rotation of the outer ring in the circumferential direction is prevented.

[0026] In an advantageous design, the bearing cover has a base body and a bearing receiving portion. The bearing receiving portion has a claw region which is connected to the base body, in particular connected to the base body in the root region of the base body. The advantage here is that the claw region projects axially on the base body, and thus the bearing receiving portion can be designed to be thin-walled and have an opening that interrupts the bearing receiving portion. In this way, higher elasticity can be achieved and thus a corresponding interference fit can be achieved, so that the outer ring can move in the axial direction with low force consumption.

[0027] In an advantageous design, the base body and the claw region are integrally formed, in particular formed as a one-piece, especially formed together as a casting. The advantage here is that simple manufacturing can be achieved.

[0028] In an advantageous design, the claw regions are spaced apart from one another in the circumferential direction by means of openings. The advantage here is that the elasticity of the claw regions is increased. In particular, the offset of the corresponding claw regions in the radial direction is simplified, that is, in particular, the elasticity at the corresponding circumferential angular positions is increased.

[0029] In an advantageous design, the bearing receiving part is tapered on its inner side. The advantage here is that, in the case of an axial movement of the floating bearing, in particular as long as the displacement remains below the critical value, the pressure acting on the outer peripheral part of the outer ring of the floating bearing does not change. Because in the case where the outer ring is positioned closer to the base body of the bearing cover, that is, when the outer ring is positioned deeper in the bearing receiving part, although the offset amount on the claw region is smaller, due to the tapered shape and thus due to the greater outward expansion when the outer ring is positioned deeper, the radial distance between the outer ring of the floating bearing and the corresponding claw region and / or the inner side of the bearing receiving part remains unchanged. However, for this purpose, the taper angle of the tapered shape should be designed appropriately, that is, in particular accurately, such that the bearing receiving part pressure acting on the outer peripheral part of the outer ring of the floating bearing is independent of the axial depth of the outer ring in the bearing receiving part.

[0030] In an advantageous design, in the axial direction, the net diameter of the bearing receiving part increases as the distance from the base body of the bearing cover decreases. The advantage here is that, in the case of an axial movement of the floating bearing, in particular as long as the displacement remains below the critical value, the pressure acting on the outer peripheral part of the outer ring of the floating bearing does not change. Because in the case where the outer ring is positioned closer to the base body of the bearing cover, that is, when the outer ring is positioned deeper in the bearing receiving part, although the offset amount on the claw region is smaller, due to the increase in the net diameter, the radial distance between the outer ring of the floating bearing and the corresponding claw region and / or the inner side of the bearing receiving part remains unchanged when the outer ring is positioned deeper. Therefore, preferably, the increase in the net diameter changes just such that the bearing receiving part pressure acting on the outer peripheral part of the outer ring of the floating bearing is independent of the axial depth of the outer ring in the bearing receiving part.

[0031] The radial direction and the circumferential direction are always referenced to the axis of rotation of the rotor shaft; the axial direction is oriented parallel to the axis of rotation of the rotor shaft.

[0032] In an advantageous design, the openings penetrate the bearing receiving part in the radial direction. The advantage here is that the claw regions can be elastically offset relative to one another independently, and thus an optimal adaptation to the outer ring can be achieved, wherein additionally the transverse forces acting on the rotor shaft can be optimally distributed over the circumference and can be led out.

[0033] In an advantageous design, a spring washer is arranged axially between the outer ring and the bearing cover, in particular the bottom of the bearing receiving part, wherein the spring washer has a coating at least on a first surface area and a second surface area, or is roughened by sandblasting, or is structured by laser, in particular having protrusions extending further in the radial direction than in the circumferential direction.

[0034] The advantage here is that safe operation can be achieved because co-rotation or slipping of the outer ring of the floating bearing is prevented. On the one hand, the outer ring of the floating bearing is arranged to be axially movable so as to withstand the thermally induced axial length change of the shaft, but on the other hand, by connecting the outer ring to the bearing receiving part of the bearing cover in a non-rotatable manner, rotation of the outer ring in the circumferential direction is prevented. Although the spring washer is axially displaced due to the thermally induced axial length change, rotation of the outer ring in the circumferential direction is prevented by means of the spring washer. This is achieved by a higher adhesion or friction that can be achieved by means of the coating, in particular compared to an uncoated spring washer which is made of a steel plate and is received in a bearing receiving part made of steel, wherein the outer ring is also made of steel. Therefore, by simply applying a rubber coating to the spring washer, a high adhesion can already be achieved between the spring washer and the bearing cover and between the spring washer and the outer ring. However, if an adhesive is used as a coating at the contact sites between the spring washer and the bearing cover and between the spring washer and the outer ring, a particularly non-rotatable connection can be achieved and thus slipping or co-rotation of the outer ring can be prevented.

[0035] In particular, the first surface areas are spaced apart from each other in the circumferential direction, wherein the second surface areas are spaced apart from each other in the circumferential direction. Here, the first surface areas are arranged on the front side of the spring washer in the axial direction, and the second surface areas are arranged on the rear side of the spring washer in the axial direction. The advantage here is

[0036] In particular, the spring washer can also be referred to as an elastic wave washer because the spring washer is designed as an annular perforated washer, the edge region of which extends in a wavy manner in the circumferential direction in the axial direction. That is, the axial position of the spring washer fluctuates as the circumferential angle increases. That is to say, the axial position of the spring washer varies as a periodic function of the circumferential angle.

[0037] In addition to the coating, surface roughening is also feasible, in particular by means of sandblasting or laser structuring. In the case of laser structuring, it is advantageous to produce structures extending elongately in the radial direction in a small range in order to prevent co-rotation of the spring washer or the outer ring of the floating bearing by means of static friction as well as possible.

[0038] In an advantageous design, the spring washer bears not only against the bearing cover, in particular against the bottom of the bearing receiving part, but also against the outer ring. The advantage here is that higher adhesion and thus torsional safety can be achieved.

[0039] In an advantageous design, the axial position of the spring washer, in particular the axial position of the median value of the region covered by the spring washer in the axial direction, is a periodic function of the circumferential angle position, in particular a non-zero function. The advantage here is that the spring washer swings back and forth periodically in the axial direction as the circumferential angle increases in the circumferential direction. Therefore, installing the spring washer between the outer ring and the bearing receiving part causes elastic deflection of the spring washer, and thus this elastic deflection adjusts or generates bearing tension. At this time, the ring axis of the spring washer, in particular the central axis, is oriented parallel to the axial direction.

[0040] In an advantageous design, the outer ring is received in the bearing receiving part in an interference fit. The advantage here is that when the length of the rotor shaft changes due to heat, the floating bearing, in particular the outer ring of the floating bearing, can move in the axial direction. At this time, it is important to keep the static friction force correspondingly low. This can be achieved by constructing the bearing receiving part in a sufficiently enlarged manner so that the outer ring can be received in an interference fit, and the tolerance of the interference fit is specified such that the floating bearing can move axially when the length changes due to heat. However, in order to prevent the outer ring from rotating in the circumferential direction with respect to the rotation axis of the rotor shaft when the bearing receiving part is constructed in an enlarged manner, the coating of the spring washer is selected such that the outer ring is connected to the bearing cover in a non-rotatable manner, in particular in the bearing receiving part, through the spring washer.

[0041] In an advantageous design, the outer ring is received in the bearing receiving part with such a precise fit that the static friction torque generated by the effective connection between the outer ring received in the bearing receiving part and the bearing cover is less than any static friction torque or the static friction torque that can be generated by the effective connection between the spring washer and the outer ring, and less than any static friction torque or the static friction torque that can be generated by the effective connection between the spring washer and the bearing cover. The advantage here is that, on the one hand, a non-rotatable material-locking and / or force-locking connection between the outer ring and the bearing cover is achieved by means of the spring washer, but on the other hand, the floating bearing can move axially without force consumption or only with low force consumption.

[0042] In an advantageous design, the coating is an adhesive, a rubber coating and / or a plastic layer. The advantage here is that a non-rotatable material-locking and / or force-locking connection between the outer ring and the bearing cover can be achieved by means of the spring washer. Preferably, a carbide layer can be used as the coating.

[0043] In an advantageous design, the coating has a metal layer. Thus, a long service life of the coating can be achieved.

[0044] In particular, the coating has a carbide layer, in particular a metal carbide layer, in particular wherein the carbide layer is applied to the surface of the spring washer roughened in particular by means of a laser, and / or wherein the carbide layer is applied to the spring washer by means of a high-speed laser metal deposition (HS-LMD) process.

[0045] In an advantageous design, the first surface region of the spring washer provided with the coating is the region of the spring washer that is at the greatest distance from the outer ring. The advantage here is that only a small amount of material is consumed, since the coating has to be provided only in the contact regions between the spring washer and the outer ring and between the spring washer and the bearing cover.

[0046] In an advantageous design, the second surface region of the spring washer provided with the coating is the region of the spring washer that is at the smallest distance from the outer ring, i.e., in particular the region of the spring washer that contacts the outer ring. The advantage here is that only a small amount of material is consumed, since the coating has to be provided only in the contact regions between the spring washer and the outer ring and between the spring washer and the bearing cover.

[0047] In an advantageous design, the spring washer is made of a steel plate, and the coating is applied to the steel plate. The advantage here is that a high modulus of elasticity can be provided. Thus, the spring washer can be manufactured in a cost-effective manner and generates a large elastic force even with a small axial displacement.

[0048] In an advantageous design, the outer ring is arranged to be movable in the axial direction, in particular movable in the axial direction in the bearing receptacle, and / or the outer ring is connected to the bearing cover by means of the spring washer in a non-rotatable manner. The advantage here is that the floating bearing is arranged to be axially movable when the length of the rotor shaft changes due to heat, even if the floating bearing is connected to the bearing cover in a non-rotatable manner, in particular by a material fit and / or a force fit.

[0049] In an advantageous design, the spring washer contacts not only the outer ring but also the bearing cover. The advantage here is that a support tension is provided by means of the spring washer, and in addition, a non-rotatable connection between the outer ring and the bearing cover is provided due to the coating.

[0050] In an advantageous design, the bearing cover is connected to the stator housing of the electric machine.

[0051] wherein, on the side of the stator housing axially facing away from the bearing cover, a bearing flange is connected to the stator housing.

[0052] wherein the outer ring of the fixed bearing is received in the bearing flange, and the inner ring of the fixed bearing is sleeved on the rotor shaft.

[0053] In particular, the inner ring of the fixed bearing abuts against the shaft step portion and is axially restricted by a stop ring disposed in the annular groove of the rotor shaft.

[0054] In particular, on the one hand, the outer ring of the fixed bearing abuts axially against the bottom of the bearing receiving portion of the bearing flange, and on the other hand, it abuts axially against a stop ring disposed in the annular groove of the bearing flange. The advantage here is that the stator housing undergoes thermally induced length changes due to the power loss of the stator winding, especially thermally induced length changes in the axial direction. Such thermally induced length changes may differ from the length changes of the rotor shaft depending on the material and geometry. For compensation, a floating bearing that can move in the axial direction is arranged.

[0055] In an advantageous design, the rotor shaft passes through a notch in the bearing cover, and the fan is non-rotatably connected to the rotor shaft on the side of the bearing cover axially facing away from the floating bearing.

[0056] Wherein, in order to seal the notch, a shaft seal ring is received in the bearing cover, especially in the notch of the bearing cover. The shaft seal ring forms a seal relative to the rotor shaft, especially by the following way: the sealing lip of the seal ring contacts the rotor shaft. The advantage here is that the bearing cover can be cooled by the air flow conveyed by the fan and thus the length change can be reduced.

[0057] In an advantageous design, the rotor shaft passes through a hole penetrating the bearing flange.

[0058] Wherein, on the side of the fixed bearing axially facing away from the floating bearing, another shaft seal ring is received in the hole. The other shaft seal ring forms a seal relative to the rotor shaft, especially by the following way: the sealing lip of the other seal ring contacts the rotor shaft. The advantage here is that the shaft seal ring received in the bearing cover and the shaft seal ring received in the bearing flange jointly seal the interior space of the electric machine relative to the environment, and thus dirt or dust that may hinder or prevent the movement of the floating bearing cannot penetrate into the bearing receiving portion.

[0059] In an advantageous design, a stator lamination stack with a stator winding is received in the stator housing. A short-circuit cage is sleeved onto the rotor shaft and is non-rotatably connected to the rotor shaft. The advantage here is that the stator housing and the rotor shaft can be affected by different degrees of heat loss according to the operating state of the electric machine. The resulting length changes can be compensated by the spring washers according to the present invention.

[0060] Further advantages are given by the dependent claims. The invention is not limited to the feature combinations of the claims. For a person skilled in the art, other reasonable combination possibilities of the claims and / or single claim features and / or features of the description and / or features of the drawings can be obtained, in particular from the object posed and / or by comparison with the prior art. Description of the Drawings

[0061] The invention will now be explained in detail with reference to the schematic drawings:

[0062] Figure 1 The electric machine according to the invention is shown in a sectional view.

[0063] Figure 2 The bearing cover 3 of the electric machine is shown in an exploded perspective view, while the spring washer 2 and the floating bearing 1 are also shown.

[0064] Figure 3 A perspective view of the spring washer 2 is shown.

[0065] Figure 4 A side view of the spring washer 2 is shown.

[0066] Figure 5 The bearing cover 51 according to the invention is shown in an exploded perspective view. Detailed Description of the Invention

[0067] As shown in the figure, the electric machine has a stator housing 9, which is connected to the bearing cover 3 at its first axial end region and to the bearing flange 8 at its other axial end region. Thus, the stator housing 9 is axially arranged between the bearing flange 8 and the bearing cover 3.

[0068] A fixed bearing 7 is received in the bearing cover 3. The inner ring of the fixed bearing is sleeved onto the rotor shaft 4 of the electric machine and abuts against the shaft step of the rotor shaft 4. The outer ring of the fixed bearing 7 is received in a bearing receiving portion formed on the bearing flange 8 and is axially limited by a stop ring arranged in an annular groove of the bearing flange 8. Another stop ring arranged in an annular groove of the rotor shaft 4 limits the inner ring of the fixed bearing. Thus, the fixed bearing is axially fixed. Therefore, the thermal expansion of the rotor shaft 4 must be compensated by the floating bearing 1.

[0069] The outer ring of the floating bearing 1 is received in the bearing cover 3. The inner ring of the floating bearing 1 is sleeved onto the rotor shaft 4 and abuts against a shaft step formed on the rotor shaft 4 on the side facing the fixed bearing.

[0070] A spring washer 2 is arranged on the side of the floating bearing 1 facing away from the fixed bearing 7. In particular, the spring washer 2 is axially arranged between the bottom of the bearing receiving portion and the outer ring of the floating bearing 1.

[0071] The spring washer 2, namely in particular a wave washer or even an elastically deformable and / or elastic wave washer, is designed as an annular perforated washer, the ring axis of which is oriented coaxially with the axis of rotation of the rotor shaft 4 and the edge region of which varies sinusoidally in the circumferential direction, in particular in that the amplitude in the axial direction varies. Namely in particular, the amplitude or the axial position of the spring washer 2 fluctuates as the circumferential angle increases. That is to say, in particular, the axial position of the spring washer 2 varies as a periodic function of the circumferential angle.

[0072] In the state installed in the electric machine, the spring washer 2 generates a supporting tension and is elastically deformed, namely in particular preloaded.

[0073] For this purpose, the spring washer 2 is made of a deformed blanked metal sheet, namely in particular an annular steel sheet body, in particular in that the perforated washer blanked out of the sheet is bent into a bent part in a wavy manner such that, with reference to the axis of rotation of the rotor shaft 4, the axial position of the spring washer 2 as a function of the circumferential angle position is a periodic function. Preferably, the periodic length in the circumferential direction is 360° / N, where N is a natural number, in particular a natural number greater than 2. Accordingly, the spring washer has N maximum parts and N minimum parts in the axial direction in the circumferential part, in particular in that the maximum parts are pressed onto the outer ring of the floating bearing 1 in an elastically preloaded manner and at the same time contact the outer ring, and the minimum parts are pressed onto the bearing cover 3 in an elastically preloaded manner and at the same time contact the bearing cover.

[0074] Therefore, the axis of rotation of the rotor shaft 4 is oriented coaxially with the ring axis of the spring washer 2 configured as a wave perforated washer.

[0075] The sheet thickness of the spring washer 2, in particular the wall thickness, is constant everywhere.

[0076] At the part of the spring washer 2 that has the maximum distance from the outer ring of the floating bearing 1, namely in particular at the minimum part, the spring washer 2 has an adhesive 30 on the side thereof facing away from the floating bearing 1.

[0077] At the part of the spring washer 2 that has the minimum distance from the outer ring of the floating bearing 1, namely in particular at the maximum part, the spring washer 2 has an adhesive 40 on the side thereof facing the floating bearing 1.

[0078] In this way, a material-locking connection is achieved between the spring washer 2 and the outer ring of the floating bearing 1 and between the spring washer 2 and the bearing cover 3. Accordingly, slipping of the spring washer 2 or co-rotation of the outer ring of the floating bearing 1 is prevented.

[0079] Here, in addition, the bearing receiving portion employs an interference fit, so that the outer ring is received in the bearing receiving portion with only low static friction. In this way, in the case of thermal expansion of the rotor shaft 4, axial movement of the outer ring of the floating bearing 1 can be achieved without the outer ring being driven. Because during axial movement, although the elastic preloading changes, the supporting tension is still provided by the spring washer 2.

[0080] In order to prevent co-rotation in the circumferential direction and the static friction torque provided by the interference fit in the bearing receiving portion for the outer ring of the floating bearing 1 is less than the critical torque, when this critical torque is exceeded, the adhesive connection between the spring washer 2 and the bearing cover 3 and / or the adhesive connection between the spring washer 2 and the outer ring of the floating bearing 1 fails.

[0081] The blower 5 is non-rotatably connected to the rotor shaft 4 on the side of the bearing cover 3 axially facing away from the fixed bearing 7. Therefore, efficient passive heat dissipation can be achieved.

[0082] The blower housing 6 surrounds the blower 5 and is connected to the bearing cover 3.

[0083] The stator 10, namely especially the stator lamination stack with a stator winding, is received in the stator housing 9.

[0084] In Figure 5 a bearing cover 51 according to the invention is shown in an exploded perspective view, on which the bearing receiving portion for the floating bearing 1, which is configured in a can shape, has openings 50 that are spaced apart from each other in the circumferential direction, especially regularly spaced apart from each other, especially axially oriented openings 50.

[0085] The bearing receiving portion projects axially on the bearing cover 51, especially on the side of the bearing cover 51 facing the fixed bearing 7, and - the same as in the embodiment according to Figures 1 to 4 - is designed integrally, especially in one piece, with the rest of the bearing cover 51.

[0086] The lateral wall portion, namely especially the can wall of the bearing receiving portion configured in a can shape, is substantially similar to a hollow cylinder, but in which axially oriented openings 50 are formed, and the inner side of the hollow cylinder has a conical shape. Here, the cone tip points to the fixed bearing 7. Thus, the net diameter of the bearing receiving portion increases with the distance from the fixed bearing 7 increasing. Thereby, it is achieved that the pressure is independent of the engagement depth of the outer ring of the floating bearing 1 in the axial direction. Therefore, if the outer ring is further pushed axially away from the fixed bearing 7, the pressure acting on the outer ring, namely especially the pressure acting on the radial peripheral portion of the outer ring from the bearing cover, remains substantially the same.

[0087] With the aid of the opening 50, the bearing receiving part consists of a plurality of claw regions which are spaced apart from one another in the circumferential direction. The claw regions transition into the remainder of the bearing cover 3, namely in particular into the base body, at their axial end regions, where the transition region is referred to as the root region.

[0088] The base body is designed as a perforated disk, wherein the rotor shaft 4 passes through the hole of the perforated disk.

[0089] Therefore, the net diameter of the bearing receiving part increases in the axial direction as the distance from the root region decreases.

[0090] Preferably, the cone angle of the cone of the bearing receiving part of the floating bearing 1 is so small that as the distance from the fixed bearing 7 increases, the increase in the net diameter in the axial direction per centimeter is less than two tenths of a millimeter, in particular less than two hundredths of a millimeter.

[0091] Preferably, the number of the openings 50 is a natural number of 3 or greater, preferably an odd number. The maximum extent of the respective opening 50 is less than 360° / N, where N is the number of openings on the circumference of the bearing receiving part. Preferably, the number N is odd.

[0092] The base body and the claw regions together with their root regions are constructed integrally, in particular constructed in one piece, in particular constructed together as a casting.

[0093] Therefore, the rotor shaft is rotatably supported by the floating bearing 1 and the fixed bearing 7.

[0094] In a further embodiment according to the invention, in the case where the bearing receiving part is designed with the opening 50, a spring washer 2 according to the Figures 1 to 5 embodiment is additionally arranged between the outer ring of the floating bearing 1 and the bearing cover 3. Thus, such a coating again enables a non-rotatable connection between the outer ring and the bearing cover by means of the spring washer 2.

[0095] By means of only a very small pressure (elastically displaceable due to the opening 50), and in particular also by means of a pressure which is always the same regardless of the axial position of the outer ring, co-rotation of the outer ring is prevented, and axial movement of the outer ring due to heat can still be achieved.

[0096] In a further embodiment according to the invention, the opening 50 is designed to be rounded at its end region facing away from the fixed bearing 7. Therefore, the opening 50 projects into the corresponding root region with the rounded end region. Thus, an improvement in fracture resistance can be achieved.

[0097] In a further embodiment according to the invention, instead of an adhesive, a rubber coating or other such coating is used, i.e., a coating which effectively connects with the material of the bearing cover or with the material of the outer ring of the floating bearing 1 to generate sufficient static friction.

[0098] Here, in order to prevent the static friction torque provided by the interference fit in the bearing receiving portion for the outer ring of the floating bearing 1 from being less than the maximum static friction torque, particularly the static friction torque in the circumferential direction, that can be provided by the friction pair, namely the spring washer 2, the bearing cover 3, and / or the outer ring of the floating bearing 1, during co-rotation in the circumferential direction.

[0099] In a further embodiment according to the invention, instead of an adhesive, a carbide layer applied by HS-LMD is used.

[0100] In a further embodiment according to the invention, instead of a coating or an adhesive, the surface is roughened. For this purpose, sandblasting or laser structuring can be used. Although sandblasting is cost-effective, laser structuring enables the generation of recesses and protrusions that extend further in the radial direction than in the circumferential direction, rather than isotropic protrusions on a microscopic scale, for increasing the static friction. Since the recesses and protrusions generated by the laser extend further in the radial direction than in the circumferential direction, a high static friction torque can be generated, thus preventing the relative rotational movement of the spring washer 2 with respect to the corresponding friction pair, namely particularly the bearing cover 3 or the outer ring of the floating bearing 1.

[0101] In an improvement, one of the above coatings can be applied to the roughened surface.

[0102] List of reference numerals:

[0103] 1 Floating bearing

[0104] 2 Spring washer

[0105] 3 Bearing cover

[0106] 4 Rotor shaft

[0107] 5 Fan

[0108] 6 Fan housing

[0109] 7 Fixed bearing

[0110] 8 Bearing flange

[0111] 9 Stator housing

[0112] 10 Stator, particularly a stator lamination stack with a stator winding

[0113] 30 Adhesive

[0114] 40 Adhesive

[0115] 50 Opening

[0116] 51 Bearing cover

Claims

1. An electric machine, which has a rotor shaft, a floating bearing and a bearing cover, Among them, the floating bearing being arranged for rotatably supporting the rotor shaft, wherein the floating bearing has an inner ring and an outer ring, in particular, rolling elements being arranged between the inner ring and the outer ring, wherein the outer ring of the floating bearing is received in a bearing receiving portion which is constructed, in particular formed, in the bearing cover, the bearing receiving portion being in particular a pot-shaped bearing receiving portion and / or designed as a blind hole, wherein the inner ring is sleeved onto the rotor shaft, characterized in that the bearing receiving portion is designed to be interrupted by openings, wherein the openings are spaced apart from each other in the circumferential direction, in particular regularly spaced apart from each other, in particular, the circumferential direction being based on the rotational axis of the rotor shaft.

2. The motor according to claim 1, characterized in that, The bearing cover has a base body and a bearing receiving portion, the bearing receiving portion having a claw region which is connected to the base body, in particular connected to the base body in the root region of the base body.

3. The motor according to any one of the preceding claims, characterized in that, The base body and the claw region are integrally formed, in particular formed as one piece, in particular formed together as a casting.

4. The electric machine according to any one of the preceding claims, characterized in that, The claw regions are spaced apart from each other in the circumferential direction by means of the openings.

5. The electric machine according to any one of the preceding claims, characterized in that, The bearing receiving portion is tapered on its inner side, wherein, in the axial direction, the net diameter of the bearing receiving portion increases as the distance from the base body of the bearing cover decreases.

6. The electric machine according to any one of the preceding claims, characterized in that The openings penetrate the bearing receiving portion in the radial direction.

7. The electric machine according to any one of the preceding claims, characterized in that A spring washer, in particular an elastic corrugated washer, is arranged between the outer ring and the bearing cover, in particular the bottom of the bearing receiving portion, in the axial direction, wherein the spring washer has a coating at least in a first surface region and a second surface region, or is roughened by sandblasting, or is structured by laser, in particular having protrusions extending further in the radial direction than in the circumferential direction, in particular, the first surface regions being spaced apart from each other in the circumferential direction, and the second surface regions being spaced apart from each other in the circumferential direction.

8. The electric machine according to any one of the preceding claims, characterized in that, The spring washer bears not only against the bearing cover, in particular the bottom of the bearing receiving portion, but also against the outer ring.

9. The electric machine according to any one of the preceding claims, characterized in that, The axial position of the spring washer, in particular the axial position of the median value of the region covered by the spring washer in the axial direction, is a periodic function of the circumferential angle position, in particular a non-zero function, and / or, the outer ring is received in the bearing receiving portion with an interference fit, and / or, the outer ring is received in the bearing receiving portion with such an exact fit that the static frictional torque generated by the effective connection of the outer ring received in the bearing receiving portion with the bearing cover is less than the static frictional torque that can be generated by the effective connection of the spring washer with the outer ring, and less than the static frictional torque that can be generated by the effective connection of the spring washer with the bearing cover, and / or, the coating is an adhesive, a rubber coating and / or a plastic layer, or, the coating has a metal layer, or, the coating has a carbide layer, in particular, the carbide layer being applied to the surface of the spring washer which is roughened by laser, and / or, the carbide layer being applied to the spring washer by means of a high-speed laser metal deposition (HS-LMD) process.

10. The electric machine according to any one of the preceding claims, characterized in that, The first surface region provided with the coating is the region of the spring washer which is at the greatest distance from the outer ring.

11. The electric machine according to any one of the preceding claims, characterized in that The second surface region provided with the coating is the region of the spring washer which is at the smallest distance from the outer ring, i.e., in particular the region of the spring washer which contacts the outer ring. and / or, The spring washer is made of a steel plate and has a coating applied thereto.

12. The electric machine according to any one of the preceding claims, characterized in that, The outer ring is arranged to be movable in the axial direction, in particular movable in the axial direction in a bearing receiving portion, and / or the outer ring is connected to the bearing cover in a non-rotatable manner by means of a spring washer. and / or, The spring washer contacts not only the outer ring but also the bearing cover.

13. The electric machine according to any one of the preceding claims, characterized in that, The bearing cover is connected to the stator housing of the electric motor. Wherein, on the side of the stator housing axially remote from the bearing cover, a bearing flange is connected to the stator housing. Wherein, the outer ring of the fixed bearing is received in the bearing flange, and the inner ring of the fixed bearing is sleeved on the rotor shaft. In particular, wherein the inner ring of the fixed bearing abuts against a shaft step and is axially limited by a stop ring arranged in an annular groove of the rotor shaft. In particular, wherein the outer ring of the fixed bearing abuts axially against the bottom of the bearing receiving portion of the bearing flange on the one hand and axially against a stop ring arranged in an annular groove of the bearing flange on the other hand.

14. The electric machine according to any one of the preceding claims, characterized in that, The rotor shaft passes through a notch in the bearing cover, and the blower is non-rotatably connected to the rotor shaft on the side of the bearing cover axially remote from the floating bearing. Wherein, in order to seal the notch, a shaft seal ring is received in the bearing cover, in particular in the notch of the bearing cover, and the shaft seal ring forms a seal relative to the rotor shaft, in particular by the following means: the sealing lip of the seal ring contacts the rotor shaft.

15. The electric machine according to any one of the preceding claims, characterized in that The rotor shaft passes through a hole penetrating the bearing flange. Wherein, on the side of the fixed bearing axially remote from the floating bearing, another shaft seal ring is received in the hole, and the other shaft seal ring forms a seal relative to the rotor shaft, in particular by the following means: the sealing lip of the other seal ring contacts the rotor shaft. and / or, A stator lamination stack having a stator winding is received in the stator housing, and a short-circuit cage is sleeved on the rotor shaft and non-rotatably connected to the rotor shaft.

Images