Stator of an electric motor, electric motor and method for manufacturing a stator

Abstract

Stator (5) of an electric motor (1) with - a basic body (12) with several poles (6) and walls (9) extending circumferentially between the poles (6), - several windings (7), each of which is supported by a pole (6) and forms a coil, - an insulating body (8) that at least partially covers the poles (6) and at least partially covers the walls (9) and - a bearing (16) with a receptacle for a shaft (2) of a rotor (3) of the electric motor (1), wherein a bearing pot (13) is provided in which the bearing (16) is arranged, wherein the bearing pot (13) is pressed into the insulating body (8), wherein the bearing pot (13) is part of a bearing bridge (10, 11) which encompasses the insulating body (8) and / or the base body (12), wherein the stator (5) has an adhesive gap (24) between the circumferential surface of the bearing pot (13) and the insulating body (8) and cured adhesive (19) arranged in the gap (24), wherein an increase in volume of the adhesive (19) resulting from the curing of the adhesive (19) exerts an expanding force on the insulating body (8).

Description

[0001] The invention relates to a stator of an electric motor. Furthermore, the invention relates to an electric motor and a method for producing a stator.

[0002] DE 10 2009 024 991 A1 discloses an electric motor with a stator and a rotor. The stator of the known electric motor has a base body with several poles and walls extending in the circumferential direction between the poles. Several windings are provided, each winding being carried by a pole and forming a coil. Furthermore, the stator of the known electric motor has an insulating body that partially covers the poles and partially covers the walls to electrically insulate the windings from the base body. The stator of the known electric motor has a bearing with an outer circumferential surface and a receptacle for the rotor shaft of the rotor of the electric motor. The bearing is arranged in a bearing cup of a bearing bridge of the stator, which encompasses the insulating body and the base body. The circumferential surface of the bearing is bonded to the inner surface of the bearing cup.A cup-shaped spacer is placed over the bearing cup and glued to it. The cup-shaped spacer is glued to the insulation body.

[0003] According to DE 10 2009 024 991 A1, the use of a spacer drastically increases the natural resonance of the system, while the wall thickness of the bearing bridge, particularly in the area where the bearing is mounted, can be kept small, ranging from a few tenths of a millimeter to two millimeters. According to DE 10 2009 024 991 A1, this should significantly reduce weight.

[0004] From DE 20 2007 000 867 U1 a stator of an electric motor is known with a base body having a plurality of poles and walls extending in the circumferential direction between the poles and a plurality of windings, wherein a respective winding is carried by a pole and forms a coil, in which an insulating body is provided which at least partially covers the poles and at least partially covers the walls and which has a bearing with a receptacle for a shaft of a rotor of the electric motor, in which the bearing is pressed into the insulating body.

[0005] DE 43 22 575 A1 relates to a bearing arrangement for electric motors, wherein at least one bearing element is provided for rotatably supporting a rotor, seated in a receptacle of a bearing receiving part of a stator. DE 2 307 991 A relates to a method for manufacturing an electric motor comprising a rotor, a housing, a bearing support, a bearing receiving bush, and a stator with a stator winding. DE 34 22 743 A1 discloses an external rotor motor for driving fans, with a cantilevered rotor and a stator connected to a motor flange, which stator consists of a stator winding and a stator core. And DE 10 2010 004 792 A1 relates to a method for securing a bearing ring to or in a component by means of an adhesive bond.

[0006] Against this background, the invention was based on the object of further simplifying the design and manufacture of an electric motor stator. Furthermore, the invention was based on the object of further reducing the weight of an electric motor stator. Furthermore, the invention was based on the object of reducing noise generation.

[0007] This object is achieved by the subject matter of the independent claims 1, 5 and 7. Advantageous embodiments are set out in the subclaims and the description below.

[0008] The invention is based on the basic finding that the stator can be stiffened by using a bearing cup for the bearing and the bearing cup is pressed into the insulation body.

[0009] A rigid stator offers the possibility of reducing noise. The press-fitting of the bearing or bearing cup according to the invention now proposes a simple way to reduce noise.

[0010] Pressing in the bearing cup results in radial tensioning of the stator. The forces applied for tensioning are directed radially outward from the stator's longitudinal axis.

[0011] The stator of an electric motor according to the invention has a base body, several windings, an insulating body and a bearing for receiving a shaft of a rotor of the electric motor.

[0012] The base body has multiple poles. In a preferred embodiment, the base body has more than two poles, particularly preferably more than three poles, particularly preferably more than four poles. The number of poles can influence the synchronous operation of the electric motor at low speeds. In a preferred embodiment, the base body has fewer than 15 poles, particularly preferably fewer than 10 poles, particularly preferably fewer than 9 poles, and particularly preferably fewer than 5 poles.

[0013] Between the poles, the stator has walls extending in the circumferential direction. In a preferred embodiment, the stator is designed as an internally slotted stator. The circumferentially extending walls are thus arranged on the outside, while the poles extend radially inward.

[0014] The axial direction of the stator is the direction perpendicular to the radial directions in which the poles extend. Particularly preferably, the axial direction of the stator is the direction that the rotor shaft is intended to take in the stator.

[0015] The stator has several windings, each of which is carried by a pole, meaning the winding is wound around the pole. Each winding forms a coil.

[0016] The insulating body of the stator according to the invention is provided for electrically insulating the windings from the base body. For this purpose, the insulating body at least partially covers the poles. Embodiments are conceivable in which the insulating body completely covers the poles. This means that no surface of the insulating body is exposed. In such an embodiment, each surface of a pole is covered by the insulating body. In a preferred embodiment, however, the poles are only partially covered. Particularly preferably, the radially inward-facing surface of the poles is not covered by the insulating body. In a preferred embodiment, only the inward-facing surface of the poles is not covered by the insulating body, while the remaining surfaces of the poles are covered by the insulating body.Furthermore, it is provided that the walls are at least partially covered by the insulating body. Here, too, embodiments are conceivable in which all surfaces of the walls of the base body are covered by the insulating body. In a preferred embodiment, however, only the radially inward-facing surfaces of the walls are covered by the insulating body, while the end faces of the base body and the outer peripheral surface of the base body are not covered by the insulating body.In a preferred embodiment, only the radially inwardly facing surfaces of the base body and sections of the end surfaces of the base body, particularly preferably the radially inner sections of the end faces of the base body, are covered by the insulating body, while other sections of the end faces of the base body, particularly the radially further outwardly located sections of the end faces of the base body and the outer peripheral surfaces of the base body, are not covered by the insulating body.

[0017] The stator according to the invention has a bearing for accommodating the rotor shaft of a rotor of the electric motor. The bearing can be a plain bearing, particularly preferably a bushing. The bearing is particularly preferably a ball bearing. The bearing has an outer circumferential surface. In the case of a ball bearing, this particularly refers to the radially outward-facing circumferential surface of the outer cage. When the bearing is designed as a plain bearing in the form of a bushing, this particularly preferably refers to the radially outward-facing circumferential surface of the bushing.

[0018] In a preferred embodiment, at least parts of the peripheral surface of the bearing cup are integrally connected to the insulation body. According to this embodiment, the bearing cup itself is directly integrally connected to the insulation body. A materially bonded connection is understood to be a connection in which the connecting partners are held together by atomic or molecular forces. A materially bonded connection is understood in particular to be a non-detachable connection that can only be separated by destroying the connecting means. A materially bonded connection can be realized in particular by soldering, welding, vulcanizing, but especially preferably by gluing. In a preferred embodiment, the adhesive used to create the materially bonded connection is a two-component adhesive, particularly preferably based on epoxy resin or an anaerobic adhesive.

[0019] The invention proposes designing the stator in such a way that the bearing cup is pressed into the insulation body. The pressing can be achieved by an oversize such that the bearing cup has, at least in one direction, relative to the distance between two opposing surfaces of the insulation body that this surface would have without contact with the peripheral surface of the bearing cup. To insert the bearing cup between these opposing surfaces of the insulation body, the distance between these surfaces must therefore be increased by spreading and / or the peripheral surface of the bearing must be pressed in, at least in the parts that come into contact with these surfaces of the bearing cup.

[0020] In a preferred embodiment, the distance between two points on the circumferential surface of the bearing pot is greater than the distance measured when the bearing pot is removed between two points on the insulation body which, when the bearing pot is installed, are in contact with the points on the circumferential surface of the bearing pot. In a preferred embodiment, the distance between two diametrically opposite points on the circumferential surface of the bearing pot is greater, particularly preferably by 1,000 ppm or by more than 10 ppm but less than 1,000 ppm, in particular by more than 50 ppm but less than 500 ppm, than the distance measured when the bearing pot is removed between two diametrically opposite points on the insulation body which, when the bearing pot is installed, are in contact with the points on the circumferential surface of the bearing pot.

[0021] Diametrically opposite points are defined as points that lie on a line that intersects the axial direction of the stator.

[0022] For pressing the bearing cup into the insulation body, it is not absolutely necessary to have a portion of the bearing cup's circumferential surface in contact with the insulation body. Embodiments are also conceivable in which the necessary oversize for pressing is achieved by applying an adhesive to the circumferential surface of the bearing cup, particularly preferably by applying an adhesive that has already partially cured. The presence of the adhesive can also lead to damping, so that rotor vibrations are not transmitted to the stator, or are transmitted only in a damped manner.

[0023] In embodiments in which at least parts of the peripheral surface of the bearing cup are firmly bonded to the insulation body, two mechanisms can be used. Pressing the bearing cup into place ensures that the bearing cup is held firmly in the insulation body. This is then complemented by the firmly bonded connection.

[0024] With regard to individual parts of the bearing's circumferential surface, embodiments are conceivable in which all parts of the circumferential surface that are materially bonded to the insulating body are also non-positively bonded to the insulating body. This is achieved by providing a gap between these parts of the bearing's circumferential surface, or the bearing cup, and the insulating body that is narrower than the thickness of an adhesive introduced into the gap once it has cured. The adhesive can occupy a smaller volume in the uncured state than in the cured state. The increase in volume during curing can lead to the generation of a non-positive connection that supports the material bond, namely to the generation of a radially acting force.

[0025] However, embodiments are also conceivable in which parts of the peripheral surface of the bearing cup are in direct contact with the insulation body and, by selecting an oversize, exert a spreading force on the insulation body. Through this connection, the bearing cup is thus connected to the insulation body in a force-locking manner. This embodiment can be supplemented by a material-to-material connection, namely an adhesive arranged in a gap between other parts of the peripheral surface of the bearing cup and the insulation body. This adhesive creates only a material-to-material connection, but not a force-locking connection, for example, because it does not change its volume or changes it only slightly during curing.

[0026] In a preferred embodiment, the insulating body is designed such that it at least partially covers the respective pole, wherein the part of the insulating body that covers the radially inner regions of a pole is not connected to the parts of the insulating body that cover the radially inner regions of the adjacent pole. In the preferred embodiments, the insulating body is grooved. This means that the insulating body has a radially inner circumferential surface interrupted by the grooves.

[0027] In an alternative embodiment of the invention, the stator of the electric motor has a bearing cup. The bearing is arranged in the bearing cup. According to the invention, the bearing cup has an outer circumferential surface, wherein at least parts of the circumferential surface of the bearing (or adhesive applied to these parts) bear against the insulating body. In a preferred embodiment, the insulating body is designed such that it at least partially covers the respective pole, wherein the part of the insulating body that covers the radially inner regions of a pole is not connected to the parts of the insulating body that cover the radially inner regions of the adjacent pole. In the preferred embodiments, the insulating body is grooved. This means that the insulating body has a radially inner circumferential surface interrupted by the grooves.According to a preferred embodiment, the bearing cup (or an adhesive applied to its circumferential surface) only bears against this radially inner circumferential surface of the insulation body. Due to the interruption of the radially inner circumferential surface by the grooves, this means that only parts of the circumferential surface of the bearing cup (or the adhesive applied thereto) bear against the insulation body, while the parts of the circumferential surface of the bearing cup located in the region of the grooves do not bear against the insulation body, but are particularly preferably designed to be exposed.

[0028] However, embodiments are also conceivable in which the part of the insulating body that covers the radially inner regions of a pole is connected to the parts of the insulating body that cover the radially inner regions of the adjacent pole, for example by means of a web. Embodiments are also conceivable in which the stator is designed with external grooves and the circumferentially extending walls between the poles are designed to be internal. These walls can be completely covered by the insulating body on the inward-facing surface. In such embodiments, the insulating body can therefore have a closed inner surface, or at least an inward-facing, closed, annular surface section. In such embodiments, the circumferential surface of the bearing cup (or an adhesive applied thereto) can bear fully against the insulating body.Furthermore, embodiments are conceivable in which the peripheral surface of the bearing cup has elevations, for example, ribs. Embodiments are conceivable in which the bearing cup is pressed into the insulation body only by the part of the peripheral surface of the bearing cup formed by the ribs (or an adhesive applied thereto), while parts of the peripheral surface of the bearing cup arranged next to the ribs have a gap—optionally filled with adhesive—between the surfaces of the insulation body facing them, which does not form a frictional connection. What has just been said regarding the ribs applies similarly to the compensation of manufacturing tolerances, for example, shape tolerances.

[0029] In a preferred embodiment, the peripheral surface of the bearing cup is cylindrical. This allows for the most even contact with the surfaces of the insulation body. However, embodiments are also conceivable in which the peripheral surface of the bearing cup is not cylindrical, for example, to achieve anti-twist protection in conjunction with the surfaces of the insulation body.

[0030] In a preferred embodiment, the surfaces of the insulation body that come into contact with the peripheral surface of the bearing cup are partial surfaces of the peripheral surface of a cylinder. This also allows for the most extensive possible contact with the peripheral surface of the bearing cup. However, embodiments are conceivable in which the surfaces of the insulation body that come into contact with the peripheral surface of the bearing cup are not partial surfaces of the peripheral surface of a cylinder. This, in conjunction with a cylindrical peripheral surface of the bearing cup, can achieve anti-twist protection.

[0031] In a preferred embodiment, the bearing is arranged axially outside the stator laminations. In an alternative embodiment, particularly in high-speed motors, especially those using SMC material, the bearing can be arranged at the level of the stator laminations or overlapping them.

[0032] In a preferred embodiment, the stator of the electric motor has an upper bearing for receiving one end of the rotor shaft of the electric motor rotor, and a lower bearing for receiving the other end of the rotor shaft of the electric motor rotor. In a preferred embodiment, the upper bearing is arranged in an upper bearing cup, wherein the upper bearing cup is pressed into the insulating body. Furthermore, the lower bearing is arranged in a lower bearing cup, wherein the lower bearing cup is pressed into the insulating body.

[0033] According to the invention, which comprises a bearing cup and a bearing arranged in the bearing cup, a gap is provided between the circumferential surface of the bearing cup and the insulating body and a cured adhesive is arranged in the gap, wherein an increase in volume of the adhesive resulting from the curing of the adhesive exerts a spreading force on the insulating body.

[0034] In a preferred embodiment, the gap between the peripheral surface of the bearing pot and the section of the insulation body to which it is integrally connected is less than 1 mm, preferably less than 0.5 mm and particularly preferably between 0.2 and 1 mm, preferably between 0.3 and 0.5 mm.

[0035] In a preferred embodiment, the insulating body has inner flanges, each of which projects beyond a winding in an axial direction of the stator. In an embodiment of the invention with a bearing arranged in a bearing cup, the spreading forces acting on the insulating body in the radial direction due to the pressing in of the bearing cup are transferred to the insulating body by the parts of the peripheral surface of the bearing cup that are in contact with the inner flanges of the insulating body or by an adhesive applied to these parts of the peripheral surface.

[0036] The inner flanges can also be designed as a circumferential ring that projects over one winding in both the axial direction of the stator and the circumferential direction of the stator.

[0037] In a preferred embodiment, the insulating body is a one-piece body, preferably a body produced by a primary forming process, for example, a body produced by injection molding. Embodiments are also conceivable in which the insulating body consists of several partial bodies. In a preferred embodiment, these are firmly connected to one another, for example, glued or welded. Particularly in embodiments in which the stator has a pole chain, the insulating body can be composed of individual partial bodies.

[0038] The bearing cup is part of a bearing bridge that surrounds the insulation body. This surrounds the bearing bridge, meaning that at least in some planes perpendicular to the stator's axial direction, parts of the bearing bridge lie outside the insulation body or outside the base body when viewed in the stator's radial direction. The resulting presence of parts of the bearing bridge outside the insulation body or base body can, in its simplest form, serve to protect parts of the insulation body or parts of the base body. The parts of the bearing bridge that surround the insulation body or base body can thus be used, for example, to form a housing. Furthermore, the use of a bearing bridge that surrounds the insulation body and / or the base body can be used to exert a preload on the insulation body or base body.If the diameter of the bearing bridge at the respective point is smaller than the outer diameter of the insulation body or the base body at this point, i.e. if there is an interference fit, the part of the bearing bridge that encompasses the insulation body or the base body can exert an inwardly directed radial force on the insulation body or the base body at this point and thus generate a prestress.

[0039] The bearing bridge is particularly preferably a stamped part, particularly preferably a stamped sheet metal part. In a preferred embodiment, the bearing bridge has a material thickness of less than 2 mm, particularly preferably less than 1.2 mm, and particularly preferably less than 0.8 mm. Embodiments are conceivable in which the bearing bridge has different material thicknesses, for example, the material thickness in the part arranged in the insulation body is greater than in the parts of the bearing bridge arranged outside the insulation body. In particular, if the pressed-in bearing bridge is essentially subjected to compressive loads, the material thickness of the part lying outside the insulation body can be reduced.

[0040] In a preferred embodiment, the base body has a stack of stator laminations. In a preferred embodiment, the base body has only one stack of stator laminations, wherein the individual stator laminations of the stack can be identically shaped and aligned. However, embodiments are also conceivable in which the individual stator laminations (sheet metal strips) are identically shaped but offset from one another. In such an embodiment, it is possible for the diameter of the stator to be greater than the width of an individual stator lamination strip. In a preferred embodiment, the individual stator laminations (sheet metal strips) of a stack of stator laminations are glued to one another.

[0041] In an alternative embodiment to the embodiment in which the base body comprises a single stack of stator laminations, the base body can be designed in multiple parts with regard to its poles, namely as a pole chain consisting of stator segments. In such an embodiment, each stator segment has its own stack of stator laminations. The individual stator segments are assembled to form a pole chain, thus forming the base body.

[0042] The base body can have a cylindrical outer peripheral surface. In a preferred embodiment, the base body has a polygonal outer peripheral surface. In a preferred embodiment, the outer peripheral surface of the base body is rotationally symmetrical, meaning that a rotation of a point on the outer peripheral surface of the base body by a specific angle around the axial direction of the stator maps this point onto another point on the outer peripheral surface of the base body.

[0043] The electric motor according to the invention has a stator according to the invention and a rotor with a shaft which is received by the bearing of the stator.

[0044] In a preferred embodiment, the electric motor is a reluctance motor.

[0045] In a preferred embodiment, the outer diameter of the rotor and the outer diameter of the bearing are of the same order of magnitude. In a preferred embodiment, the difference between the outer diameter of the rotor and the outer diameter of the bearing is less than 10%, particularly preferably less than 5%. Embodiments are conceivable in which the outer diameter of the rotor is minimally larger than the outer diameter of the bearing, as are embodiments in which the outer diameter of the bearing is minimally larger than the outer diameter of the rotor. In a preferred embodiment, the outer diameter of the rotor corresponds to the outer diameter of the bearing. The outer diameter of the rotor is referred to in particular as the largest diameter of an envelope (a covering) that encloses the rotor.The outer diameter of the rotor can also be the diameter of the hollow cylinder with the smallest inner diameter that can still be pushed onto the rotor. The outer diameter of the bearing is specifically the largest diameter of an envelope that encloses the bearing. The outer diameter of the bearing can also be the diameter of the hollow cylinder with the smallest inner diameter that can still be pushed onto the bearing. The outer diameter of the bearing cup is specifically the largest diameter of an envelope that encloses the bearing cup. The outer diameter of the bearing cup can also be the diameter of the hollow cylinder with the smallest inner diameter that can still be pushed onto the bearing cup.

[0046] The method according to the invention for producing a stator according to the invention provides that, starting from a base body with a plurality of poles and walls extending in the circumferential direction between the poles, and a plurality of windings, each winding being carried by a pole and forming a coil, and an insulating body which at least partially covers the poles and at least partially covers the walls, a bearing pot for a bearing with a receptacle for a shaft of a rotor of the electric motor is pressed into the insulating body.

[0047] In a preferred embodiment, the bearing cup can be inserted into the insulating body, forming a gap between the peripheral surface of the bearing cup and the insulating body. A not yet cured adhesive can be introduced into the gap and cured. In this way, the adhesive firmly bonds at least parts of the peripheral surface of the bearing cup to the insulating body.

[0048] According to an alternative, at least parts of the peripheral surface of the bearing cup are coated with an adhesive, and the bearing cup is inserted into the insulation body. The adhesive is then cured. The cured adhesive on the peripheral surface of the bearing cup bonds parts of the peripheral surface of the bearing cup to the insulation body.

[0049] In a preferred embodiment, the annular gap formed between the outer ring of the bearing and the inner wall of the bearing cup can be filled with an adhesive, either by applying the adhesive to the inside of the cup wall or to the outside of the outer ring, or by injecting the adhesive into the annular gap. The adhesive can initially serve to pre-fix the bearing in the bearing cup on the bearing bridge side before it hardens.

[0050] The adhesive provided in the gap can be used before it has hardened for an exact coaxial alignment of the rotor axis to the stator and thus a corresponding exact alignment of the rotor shaft and the rotor carried by the rotor shaft in the stator. For this purpose, a unit consisting of the rotor shaft and rotor, together with the bearings fixed to the rotor shaft, can be designed to be displaceable in the adhesive beds of the bearing cups in both radial and axial directions, and can also be tiltable. The respective adhesive gaps allow for appropriate alignment of the bearings in the bearing cups, whereby this rotor shaft position is fixed once an exact rotor shaft alignment is achieved and the adhesive has hardened. At the same time, an exact alignment of the associated bearing bridge can also be achieved by bonding the outer circumferential surface of the bearing cup to the insulation body while leaving an adhesive gap.

[0051] In a preferred embodiment of the method according to the invention, the outer wall of the bearing pot can be wetted with adhesive and the bearing pot can be pressed into the insulation body.

[0052] In a preferred embodiment of the method according to the invention, an assembly device can fix the rotor and stator relative to each other in a desired position. The inner walls of the bearing cups can be coated with an adhesive in a subsequent step. In a subsequent step, the bearings can be pressed onto the rotor shaft. This ensures that they assume a fixed position with respect to the respective rotor shaft end and also with respect to each other.

[0053] In a preferred embodiment of the method according to the invention, the axial alignment of the rotor, rotor shaft and bearings to the bearing bridges can be carried out in a further step with regard to the gap between the rotor and the poles.

[0054] The electric motor according to the invention is preferably used in household appliances, particularly preferably in vacuum cleaners, for example in blower motors of vacuum cleaners, fans, hair dryers, or kitchen appliances, particularly preferably in food processors or mixers. In principle, the electric motor according to the invention, when designed as a reluctance motor, is suitable for all applications of such reluctance motors, in particular for hybrid drives, washing machines, and pumps.

[0055] The invention is explained in more detail below with reference to a drawing which merely illustrates exemplary embodiments.

[0056] Showing: Fig. 1 is a perspective exploded view of an electric motor according to the invention, Fig. 2 the assembled electric motor in a perspective view, Fig. 3 is a plan view of the assembled electric motor according to Fig. 2; Fig. 4 a sectional side view of the electric motor according to the invention according to Fig. 2 cut according to line IV-IV in Fig. 3 and Fig. 5 an enlarged, partially sectioned side view of area V of the Fig. 4.

[0057] The Fig. The electric motor 1 shown in Figure 1 is a 4 / 2-phase reluctance motor. The electric motor 1 has a rotor 3 mounted on a rotor shaft 2 for rotation therewith. The rotor 3 has two diametrically opposed rotor poles 4. During operation of the electric motor, the rotor 3 rotates about a geometric rotor axis X defined by the rotor shaft 2, which also corresponds to the axial direction of the stator 5.

[0058] The stator 5 surrounding the rotor 3 has four poles 6, each at an angle of 90° to each other in the direction of rotation of the rotor 3. These poles each carry windings 7 forming coils.

[0059] For electrical insulation of the windings 7 from the stator 5, the poles 6 and the walls 9 extending between the poles 6 in the circumferential direction are at least partially covered by an insulating body 8 formed as a plastic injection-molded part. The poles 6 and the walls 7 extending between the poles 6 in the circumferential direction form a base body 12 of the stator 5. As can be seen from the perspective view of the Fig. 1, the insulating body 8 is designed in such a way that it leaves parts of the end faces of the base body 12 as well as the entire outer circumferential surface of the base body 12 exposed. The stator 5 has an upper bearing bridge 10 and a lower bearing bridge 11. The bearing bridges 10, 11 surround the insulating body 8 and the base body 12. As the Fig. 2 and the Fig. 4, the bearing bridges 10, 11 are connected to each other via connecting elements 20. The respective bearing bridge 10, 11 has a bearing cup 13 through which the rotor shaft 2 passes. The cup bottom 14 of the bearing cup 13 extends essentially horizontally, i.e. in a transverse plane to the rotor axis X. As the Fig. 4 and the Fig. 5, the bearing cup 13 is inserted between the insulating body 8 during assembly of the electric motor. In the embodiment shown here, the cup wall 15 surrounding the edge of the cup base 14 is aligned vertically with respect to the base plane of the top base 14. In the end region of the cup wall 15 facing away from the cup base 14, this wall merges into radially outwardly extending bridge sections of the respective bearing bridge 10, 11. Each bearing cup 13 serves to accommodate a bearing 16, in particular a rolling or plain bearing. A ball bearing is shown in each of the drawings.

[0060] The inner diameter of the bearing cup 13 is slightly larger than the outer diameter of the bearing 16, so that the bearing 16 can be displaced and tilted transversely to the rotor axis X within the bearing cup 13 without additional means. The inner diameter of the cup is selected such that, when the bearing 16 is inserted, a circumferential gap of approximately 0.2 to 1 mm, preferably approximately 0.3 mm, is created. The cup height, viewed in the axial direction, is thus adapted to the thickness of the bearing 16, viewed in the same direction, so that the thickness of the bearing 16 can be fully accommodated in the bearing cup 13.

[0061] Each bearing 16 is pressed onto the rotor shaft 2 in the region of the inner ring 17 through which the rotor shaft 2 passes in the illustrated embodiment.

[0062] The annular gap formed between the outer ring 18 and the pot wall is filled with an adhesive 19, which is applied either to the inside of the pot wall 15 or to the outside of the outer ring 18. Alternatively, the adhesive 19 can also be injected into the annular gap.

[0063] The adhesive 19 initially serves to pre-fix the bearing 16 in the bearing cup 13 on the bearing bridge side before it hardens.

[0064] The inner diameter of the insulation body 8 is selected to be larger than the outer diameter of the pot wall 15 (the outer circumferential surface of the bearing pot), so that, when inserted, a circumferential gap with a radial width of 0.2 to 1 mm, preferably 0.3 to 0.5 mm, is formed between the insulation body 8 and the pot wall 15. The resulting adhesive gap 24, like the adhesive gap between the bearing 16 and the pot wall 15, is filled with adhesive 19, which is applied to the inside of the wall of the insulation body 8 and / or the outside of the pot wall 15. This adhesive bond can serve to pre-fix the components before curing. The insulating body 8 has inner flanges 21, each of which projects beyond a winding 7 in the axial direction of the stator 5, wherein the bearing pot 13 is integrally connected to the inner flanges 21 by means of the adhesive connection.

[0065] The gap-filling adhesive 19 provided in the respective adhesive gaps 24 allows, before curing, an exact coaxial alignment of the rotor axis X to the stator 5 and, accordingly, an exact alignment of the rotor shaft 2 and the rotor 3 carried by the rotor shaft 2 in the stator 5.

[0066] For this purpose, the rotor shaft-rotor unit, together with the bearings 16 secured to the rotor shaft 2, can be displaced in both the radial and axial directions within the adhesive beds of the bearing cups 13, and can also be tilted. The respective adhesive gaps 24 allow for the corresponding alignment of the bearings 16 within the bearing cups 13, whereby this rotor shaft position is fixed after achieving precise rotor shaft alignment and curing of the adhesive 19. The circumferential adhesive gap 24 between the bearing cup 13 and the bearing 16 may have different radial widths around the circumference.

[0067] At the same time, an exact alignment of the associated bearing bridge 10 or 11 can also be achieved by bonding the outer circumferential surface of the bearing cup 13 to the insulation body 8 while leaving an adhesive gap 24.

[0068] Starting from a finished and first joined base body 12 with several windings and an insulation body 8, the further assembly is carried out after loose insertion of the rotor 3 as follows: The outer wall of the bearing cup 13 is coated with adhesive, in particular a two-component epoxy resin-based adhesive, and pressed into the receptacle of the insulation body 8. Due to the press fit, there is no gap.

[0069] The adhesive hardens within three to five minutes to the point where the supporting fixation provided by the press fit is sufficient for rapid further assembly.

[0070] In the next assembly step, the same procedure is followed with the second bearing bridge 11, so that after its fixation and subsequent fixing of the bearing bridges 10, 11 to one another, for example by welding, the base body of the stator 5 is encompassed by the bearing bridges.

[0071] A mounting fixture fixes the rotor 3 and the stator 5 relative to each other in the desired position. The inner walls of the bearing cups 13 are coated with an anaerobic adhesive. This type of adhesive is characterized by curing after metal-to-metal contact in the absence of air. The curing time can be greatly reduced by adding an activator (e.g., copper salt). The bearings 16 are pressed onto the rotor shaft 2 and, with respect to a rotor shaft end, assume fixed positions relative to the respective end and also relative to each other.

[0072] In a further step, the axial alignment of rotor 3, rotor shaft 2, and bearings 16 relative to the bearing bridges 10, 11 is carried out, taking into account the gap between rotor 3 and poles 6. A gap of approximately 0.3 mm between the bearing outer ring and the respective bearing cup 13 is used for this purpose. Once this alignment is complete, the positions relative to one another are fixed using a clamp or similar device, and the adhesive in the gaps around the bearings 16 is selectively moistened with activator, so that curing is complete after approximately two minutes. The clamped components move into a waiting position for a short curing period, after which the clamps are removed. The exact coaxial alignment of rotor 3 and stator 5 is then fixed.

[0073] The selected adhesive gaps 24, which are provided with gap-filling adhesive 19, allow manufacturing tolerances to be compensated for in a favorable manner during assembly.

Claims

[1] Stator (5) of an electric motor (1) with - a base body (12) with several poles (6) and walls (9) extending in the circumferential direction between the poles (6), - a plurality of windings (7), each winding (7) being carried by a pole (6) and forming a coil, - an insulating body (8) which at least partially covers the poles (6) and at least partially covers the walls (9) and - a bearing (16) with a receptacle for a shaft (2) of a rotor (3) of the electric motor (1), wherein a bearing cup (13) is provided in which the bearing (16) is arranged, wherein the bearing cup (13) is pressed into the insulating body (8), wherein the bearing cup (13) is part of a bearing bridge (10, 11) which engages around the insulating body (8) and / or the base body (12), wherein the stator (5) has an adhesive gap (24) between the circumferential surface of the bearing cup (13) and the insulating body (8) and cured adhesive (19) arranged in the gap (24), wherein an increase in volume of the adhesive (19) resulting from the curing of the adhesive (19) exerts a spreading force on the insulating body (8). [2] Stator (5) according to claim 1, characterized by that the bearing pot (13) has an outer circumferential surface and at least parts of the circumferential surface of the bearing pot (13) are materially connected to the insulating body (8). [3] Stator (5) according to claim 1 or 2, characterized by in that the insulating body (8) has inner flanges (21) which each project beyond a winding (7) in an axial direction of the stator (5), wherein the spreading forces acting on the insulating body (8) in the radial direction by pressing in the bearing pot (13) are transmitted to the insulating body (8) by the parts of the circumferential surface of the bearing pot (13) which are in contact with the inner flanges (21) of the insulating body (8). [4] Stator (5) according to one of claims 1 to 3, characterized by that the bearing (16) is a ball bearing. [5] Electric motor (1) with a stator (5) according to one of claims 1 to 4 and a rotor (3) with a shaft (2) which is received by the bearing (16) of the stator (5). [6] Electric motor (1) according to claim 5, characterized by that the outer diameter of the rotor (3) corresponds to the outer diameter of the bearing (16). [7] Method for producing a stator (5) according to one of claims 1 to 4, characterized by that starting from a base body (12) with a plurality of poles (6) and walls (9) extending in the circumferential direction between the poles (6) and a plurality of windings (7), wherein a respective winding (7) is carried by a pole (6) and forms a coil, and an insulating body (8) which at least partially covers the poles (6) and at least partially covers the walls (9), a bearing pot (13) for a bearing (16) with a receptacle for a shaft (2) of a rotor (3) of the electric motor is pressed into the insulating body (8). [8] Method according to claim 7, characterized bythat, before pressing the bearing pot (13) into the insulation body (8), an adhesive (19) which has not yet hardened is applied to parts of the circumferential surface or to the complete circumferential surface of the bearing pot (13) and / or an adhesive (19) which has not yet hardened is applied to parts of the surface of the insulation body (8) which come into contact with the circumferential surface of the bearing pot (13) during pressing.

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