DE102021115837A1 - Electric motor and method of manufacturing an electric motor - Google Patents

Abstract

An electric motor is proposed, the electric motor having a rotor with a rotor shaft, a magnet, a centering part for the magnet and a balancing weight, the centering part and the balancing weight being press-connected to one another only in sections in the circumferential direction. In addition, a method for producing an electric motor is proposed, a balancing weight for a rotor shaft being machined at least partially by turning out-of-round in such a way that the balancing weight has an out-of-round pressing surface.

Description

The present invention relates to an electric motor, in particular for a fan, according to the preamble of claim 1 and a method for producing an electric motor.

Electric motors, for example in the form of brushless DC motors, are known from the prior art and have a stator and a rotor rotating relative to the stator. In brushless DC motors, the stator is fitted with stator coils and the rotor with permanent magnets.

In the case of electric motors, imbalances in the rotating components can lead to vibrations and the resulting increased wear, especially of the bearings. To compensate for these imbalances, the rotating components of an electric motor are usually balanced, with the compensation being able to take place by applying balancing weights and/or by removing material.

The material can be removed on components specially designed for this purpose. In particular, balancing weights, for example in the form of balancing rings or disks made of metal, can be used, with material being removed from the balancing weights by drilling, grinding, milling or the like.

the DE 10 2017 122 466 A1 discloses such an electric motor with a stator and a rotor, the rotor having a rotor shaft, a balancing disk pressed onto the rotor, a permanent magnet and a sleeve. The sleeve, together with the permanent magnet pressed into the sleeve, is press-connected to the balancing disk in such a way that the permanent magnet is non-rotatably connected to the rotor shaft and is centered relative to the rotor shaft.

However, it has been shown that with such designs, stresses can occur, which can lead to a bending of the rotor shaft. The resulting imbalance can vary during operation of the electric motor due to a change in the state of tension and can therefore not or not completely be compensated for by balancing.

The present invention is therefore based on the object of specifying an improved electric motor in which the risk of the formation of (dynamic) imbalances during operation of the electric motor, in particular due to tension in the rotating components, is reduced and/or the service life of the electric motor is increased, preferably with a cost-effective manufacturing process of the electric motor is made possible.

The object on which the invention is based is achieved by an electric motor according to claim 1 or a method according to claim 11 . Advantageous developments are the subject of the subclaims.

The proposed electric motor has a (fixed) stator and a rotor which can rotate about an axis of rotation relative to the stator. The rotor has a rotor shaft, an in particular cylindrical (permanent) magnet, an in particular sleeve-like or cylindrical centering part for centering the magnet relative to the rotor shaft and at least one in particular ring-shaped balancing weight, the balancing weight being non-rotatable, in particular by means of a force fit and/or by a Press connection/press fit, connected to the rotor shaft, in particular pressed onto the rotor shaft, and the centering part is non-rotatably connected to the balancing weight by a press fit/press connection, in particular pressed onto the balancing weight or a pin of the balancing weight.

It is proposed to press-connect the centering part and the balancing weight to one another in a common fastening plane orthogonal to the axis of rotation or in the circumferential direction only in sections or at a plurality of press/connection sections spaced apart from one another or to connect them non-positively or by means of a press fit (radial).

In contrast to the prior art, the electric motor according to the invention does not provide for the centering part and the balancing weight to be joined in the circumferential direction over the entire surface or over the entire (circular-cylindrical) joining/active/pressing surface, but only in sections with a force fit or by a press fit associate.

In this way, the pressing forces/pressures and the resulting stresses in the rotor shaft and thus the risk of the rotor shaft bending can be reduced, preferably without changing the press fit or the manufacturing tolerances of the centering part and the balancing weight. It has been shown that such a design nevertheless enables (sufficient) centering of the magnet by means of the centering part and the balancing weight relative to the rotor shaft.

The balancing weight has a first and the centering part has a second joining/acting/pressing surface, hereinafter always referred to as the pressing surface, where the centering part and the balancing weight - in particular exclusively - are non-positively or non-rotatably (directly) connected to one another (press) via the pressing surfaces, in particular in such a way that a torque can be transmitted from the balancing weight to the centering part or the magnet.

In particular, it is provided that the pressing surfaces in the circumferential direction press radially against one another only in sections and preferably only bear radially on one another in sections or are radially spaced from one another in sections.

The spatial assignments, arrangements and/or orientations, in particular the terms "radial", "axial" and/or "in the circumferential direction" used in the context of the present invention, relate - unless otherwise stated - in particular to the axis of rotation of the rotor or the rotor shaft.

The term "press connection" or "press joining" or "press fit" in the sense of the present invention refers to a non-rotatable/non-positive, in particular backlash-free, connection of two components, in particular the balancing weight with the rotor shaft and/or the centering part with the balancing weight Understand, in particular the components connected to one another in this way are at least essentially elastically deformed and/or an unintentional loosening of the components connected to one another is prevented by adhesion or the acting frictional forces.

A press connection between two components, in particular the balancing weight with the rotor shaft and/or the centering part with the balancing weight, can be achieved by pressing one component onto the other component (longitudinal interference fit) and/or by shrinking and/or cold or expanding the components (transverse interference fit ) take place.

Preferably, one of the pressing surfaces, in particular the pressing surface of the balancing weight, is non-round and/or - in a top view or in a view parallel to the axis of rotation - at least essentially polygonal or polygonal-cylindrical or hypotrochoid-shaped or hypotrochoidal-cylindrical and the other pressing surface, in particular the pressing surface of the centering part, at least essentially round and/or - in a top view or in a view parallel to the axis of rotation - circular or circular-cylindrical, in particular in such a way that the pressing surfaces in the circumferential direction only partially or on several pressing sections spaced apart from one another (radially) touch or press against each other.

Provision is therefore made in particular for the pressing surfaces to have regions in the circumferential direction in which they do not press against one another or bear against one another and are radially spaced apart from one another.

The rotor particularly preferably has a plurality of, in particular two, balancing weights, preferably with the balancing weights being of identical construction and/or the centering part and/or the magnet being/is arranged (axially) between the balancing weights.

In particular, the centering part can be connected axially or at the axial ends in a torque-proof manner to a balancing weight, the centering part being press-connected to each balancing weight in the circumferential direction only in sections. Corresponding advantages are realized in this way.

However, it is also possible for the second or additional balancing weight to be formed in one piece with the centering part.

In the proposed method for producing an electric motor, in particular the proposed electric motor, a balancing weight, in particular the pressing surface of the balancing weight, is machined/manufactured at least partially by non-circular turning, in particular polygonal or polygon turning, in particular in such a way that the balancing weight is non-circular, in particular has at least substantially polygonal or polygonal-cylindrical or hypotrochoid-shaped or hypotrochoid-cylindrical pressing surface for the centering part. As a result, the balancing weight and the centering part for centering the magnet can be connected to one another in such a way that the centering part and the balancing weight are only partially press-connected to one another in a fastening plane orthogonal to the axis of rotation or in the circumferential direction.

Out-of-round turning enables the balancing weight or the pressing surface of the balancing weight to be produced in a particularly cost-effective manner. In particular, by turning the balancing weight out of round, an additional manufacturing step by milling the pressing surface can be dispensed with.

The aforementioned aspects and features as well as the aspects and features of the present invention resulting from the claims and the following description can in principle be implemented independently of one another, but also in any combination.

• 1 einen schematischen Schnitt eines Gebläses mit einem erfindungsgemäßen Elektromotor entlang einer Rotationsachse;
• 2 eine Explosionsdarstellung einiger Bauteile des Gebläses/Elektromotors gemäß 1;
• 3 eine schematische Seitenansicht eines Rotors des erfindungsgemäßen Gebläses/Elektromotors;
• 4 eine Explosionsdarstellung des Rotors gemäß 3;
• 5 einen schematischen Schnitt des Rotors gemäß 3 entlang der Rotationsachse;
• 6 eine schematische Seitenansicht eines Wuchtgewichts des Rotors gemäß 3;
• 7 eine perspektivische Ansicht des Wuchtgewichts gemäß 6;
• 8 eine schematische Ansicht eines hypotrochoidförmigen Profils;
• 9 eine schematische Draufsicht des Wuchtgewichts gemäß 6; und
• 10 einen schematischen Schnitt des Wuchtgewichts entlang der Schnittlinie X-X gemäß 9.

Further aspects, advantages, features, properties and advantageous developments of the present invention result from the claims Chen and the following description of a preferred embodiment based on the figures. It shows in a schematic representation, not true to scale:

• 1 a schematic section of a fan with an electric motor according to the invention along an axis of rotation;
• 2 an exploded view of some components of the blower/electric motor according to 1 ;
• 3 a schematic side view of a rotor of the fan / electric motor according to the invention;
• 4 an exploded view of the rotor according to 3 ;
• 5 according to a schematic section of the rotor 3 along the axis of rotation;
• 6 a schematic side view of a balancing weight of the rotor according to 3 ;
• 7 a perspective view of the balancing weight according to FIG 6 ;
• 8th a schematic view of a hypotrochoid profile;
• 9 a schematic top view of the balancing weight according to FIG 6 ; and
• 10 according to a schematic section of the balancing weight along section line XX 9 .

In the figures, some of which are not true to scale and are only schematic, the same reference numbers are used for identical, identical or similar parts and components, with corresponding or comparable properties or advantages being achieved even if repetition is dispensed with.

1 shows a proposed electric motor 1 or a proposed fan 2 with a proposed electric motor 1 in a schematic sectional view.

The proposed electric motor 1 is preferably used to drive the fan 2 or to convey gas, in particular air. The electric motor 1 or the fan 2 in a vacuum cleaner (not shown) is particularly preferably used to generate a negative pressure.

However, it is also possible to use the electric motor 1 to drive other devices, such as a food processor.

The blower 2 preferably has a housing 3, an impeller/impeller 4 and an optional diffuser 5.

The impeller 4 is preferably arranged within the housing 3 and can be rotated about an axis of rotation A relative to the housing 3 and/or the diffuser 5 . The impeller 4 is preferably driven directly by the electric motor 1 .

In order to supply mechanical work to the gas flowing into the housing 3 or to convey the gas, the fan 2 , in particular the fan wheel 4 , preferably has a plurality of rotor blades 6 .

The diffuser 5, which is preferably arranged downstream of the impeller 4, is equipped with a plurality of guide vanes 7, in particular in order to reduce the swirl of the gas exiting the impeller 4 or the pressure exit losses.

As already explained, the electric motor 1 is designed to drive the fan 2 , in particular the impeller 4 .

In the illustrated embodiment, the electric motor 1 is designed as a brushless DC motor. In principle, however, other solutions are also possible.

The electric motor 1 has a (stationary) stator/stator 8 and a (rotating) rotor/runner 9, preferably with the rotor 9 being arranged at least partially within the stator 8 and being rotatable about the axis of rotation A relative to the stator 8.

The stator 8 has, in particular, a multi-part housing 10, several windings/coils 11, here four, a magnetic core 12 and/or a printed circuit board 13.

Like in particular the in 2 illustrated exploded view shown, the magnet core 12 preferably comprises a plurality of stacked electrical laminations, which form a plurality, here four, coil carrier, each winding / coil 11 is wound around a coil carrier. The coils 11 and the magnetic core 12 are fastened in or on an optional holder 14, preferably with the holder 14 being made of plastic, in particular injection molded.

The housing 10 for the stator 8 preferably has a first housing part 15 and a second housing part 16, in particular with the first housing part 15, the holder 14, the second housing part 16 and/or the printed circuit board 13 being positively, non-positively and/or materially connected , In particular by plugging together or without screws, are connected to each other.

In the illustrated embodiment, the first housing part 15 is plugged onto the second housing part 16 and the printed circuit board 13 by means of the holder 14 . However, other solutions are also possible here.

The electric motor 1 preferably has a plurality of bearings 17, 18, the rotor 9 being rotatably connected to the stator 8, in particular the housing 10, via the bearings 17, 18. In the illustrated embodiment, the bearings 17, 18 are designed as ball bearings. However, other solutions are also possible.

Preferably, the first housing part 15 is designed to accommodate a first bearing 17 and the second housing part 16 to accommodate a second bearing 18, such as in particular 1 illustrated.

The following is based on the 3 until 5 the structural design of the rotor 9 is explained in more detail.

3 shows a schematic side view of the rotor 9. 4 shows an exploded view of the rotor 9. 5 shows a schematic section of the rotor 9 along the axis of rotation A.

The electric motor 1, in particular the rotor 9, has a rotor shaft 19, a (permanent) magnet 20, a centering part 21 and at least one balancing weight 22, 23.

In the illustrated embodiment, the electric motor 1 or the rotor 9 has a first balancing weight 22 and a second balancing weight 23, the balancing weights 22, 23 preferably being of identical design. In particular, the second balancing weight 23 can have one, several or all features of the first balancing weight 22 or vice versa. The explanations for one balancing weight 22, 23 therefore preferably also apply correspondingly to the other balancing weight 22, 23, even if repetition is dispensed with below.

As already explained, the rotor 9 - in particular together with the magnet 20, the centering part 21 and/or the balancing weight 22, 23 - can be rotated about the axis of rotation A relative to the stator 8.

The axis of rotation A preferably forms a longitudinal, symmetrical and/or central axis of the preferably rotationally symmetrical rotor 9, the preferably rotationally symmetrical rotational shaft 19, the preferably rotationally symmetrical magnet 20, the preferably rotationally symmetrical centering part 21 and/or the preferably ring-shaped balancing weight 22, 23.

Preferably, some or all components of the rotor 9, in particular the magnet 20, the centering part 21, the balancing weight 22, 23 and/or the bearings 17, 18 are pushed (axially) onto the rotor shaft 19 and/or - directly or indirectly - on the Rotor shaft 19 attached.

The magnet 20, the centering part 21, the balancing weight 22, 23 and/or the bearings 17, 18 or the inner rings of the bearings 17, 18 are/is particularly preferably non-rotatable, directly or indirectly, in particular by a force fit or by a press fit /Press connection, connected to the rotor shaft 19, in particular (axially) pressed onto the rotor shaft 19.

It is preferable for the balancing weight 22, 23 to be attached directly and the magnet 20 and/or the centering part 21 to be attached indirectly to the rotor shaft 19. The magnet 20 is particularly preferably attached to the rotor shaft 19 via the centering part 21 and the centering part 21 via the balancing weight 22, 23, as will be explained in more detail below.

For the assembly/fastening of the individual components, in particular the magnet 20, the centering part 21, the balancing weight 22, 23 and/or the bearings 17, 18, the rotor shaft 19 has several areas/sections/seats.

How in particular 4 As illustrated, the rotor shaft 19 preferably has a first bearing seat 19A for the first bearing 17, a second bearing seat 19B for the second bearing 18, a first press fit 19C for the first balancing weight 22, a second press fit 19D for the second balancing weight 23 and/or a optional adhesive surface 19E for the magnet 20, preferably wherein the adhesive surface 19E is provided between the press seats 19C, 19D and/or the bearing seats 19A, 19B.

The electric motor 1 or the rotor 9 can preferably be balanced at least partially by means of the balancing weight 22, 23—in particular by removing material on the balancing weight 22, 23.

In addition, the magnet 20 can be aligned relative to the rotor shaft 19 by means of the balancing weight 22 , 23 and the centering part 21 . In particular, the magnet 20 can be attached to the rotor shaft 19 at least essentially coaxially by means of the centering part 21 and the balancing weight 22, 23.

The balancing weight 22, 23 is preferably ring-shaped or as a (circular/closed) ring and has in particular an at least essentially circular-cylindrical inner surface 22A, 23A, preferably wherein the balancing weight 22, 23 is connected to the rotor shaft 19, in particular the press fit 19C or 19D, via the inner surface 22A, 23A in a rotationally fixed manner, in particular in a non-positive manner.

The first balancing weight 22 is preferably pressed in a rotationally fixed manner, in particular in a non-positive manner, onto the first press fit 19C and the optional second balancing weight 23 is pressed in a rotationally fixed manner, in particular in a non-positive manner, on the second press fit 19D.

The structure of the balancing weight 22, 23 is later in connection with the 6 until 10 explained in more detail.

The magnet 20 is preferably designed as a (circumferential/closed) ring or hollow cylinder, preferably with the magnet 20 having oppositely magnetized sections/poles (not shown) in the circumferential direction.

The magnet 20 is preferably designed as a permanent magnet and can be made of neodymium-iron-boron, for example.

Magnet 20 preferably has an at least essentially circular-cylindrical inner surface 20A and/or an at least essentially circular-cylindrical outer surface 20B, preferably with inner surface 20A facing rotor shaft 19 and/or facing away from centering part 21 and/or outer surface 20B facing away from rotor shaft 19 and/or facing the centering part 21 .

Preferably, the magnet 20 is/is centered by means of the centering part 21 relative to the rotor shaft 19 or the axis of rotation A, in particular in such a way that the magnet 20, in particular the longitudinal/symmetry/central axis of the magnet 20, is at least essentially coaxial to the rotor shaft 19, in particular the rotational thing A, is aligned.

The centering part 21 is preferably designed as a thin-walled hollow cylinder, in particular as a (reinforcement) sleeve.

Centering part 21 preferably has an at least essentially circular-cylindrical inner surface 21A and/or an at least essentially circular-cylindrical outer surface 21B, preferably with inner surface 21A of centering part 21 bearing directly and/or radially against outer surface 20B of magnet 20 or pressing against it .

The centering part 21 is preferably made of corrosion-resistant and/or non-ferromagnetic steel.

The magnet 20 is preferably at least partially, in particular completely, pressed into the centering part 21 and/or non-positively or non-rotatably connected to the centering part 21 by a press fit.

How in particular 5 As illustrated, the outer surface 20B of the magnet 20 is preferably in contact with the inner surface 21A of the centering part 21 over the entire surface or over the entire longitudinal extent.

However, it is preferred that the magnet 20, in particular the inner surface 20A, is not connected to the rotor shaft 19 in a non-positive manner or by a press fit, but rather between the magnet 20, in particular the inner surface 20A of the magnet 20, and the rotor shaft 19 (radial -) There is play or an (annular) gap is provided. In this way, any stresses between the magnet 20 and the rotor shaft 19, which can occur during operation in particular due to a different expansion of the components, are avoided.

Optionally, the magnet 20, in particular the inner surface 20A of the magnet 20, is connected to the rotor shaft 19, in particular the adhesive surface 19E, in a materially bonded manner or by gluing.

In this way it is possible to fix the magnet 20 axially on the rotor shaft 19 without tension occurring between the magnet 20 and the rotor shaft 19 during operation of the electric motor 1 . The adhesive can advantageously at least partially compensate for different changes in the geometric dimensions of the rotor shaft 19 and magnet 20 when the components are heated.

As already explained, the centering part 21 is designed to center or align the magnet 20 relative to the rotor shaft 19 . In addition, the magnet 20 is protected from corrosion and/or damage by means of the centering part 21 .

The centering part 21 preferably encases/surrounds the magnet 20 radially—in particular over the entire longitudinal extension of the magnet 20—towards the outside. In particular, the magnet 20 is arranged between the rotor shaft 19 and the centering part 21 .

The centering part 21 preferably forms a reinforcement or a reinforcement sleeve for the magnet 20.

How in particular 5 illustrated, the centering part 21 is preferably longer than the magnet 20 and/or the centering part 21 protrudes axially beyond the magnet 20, in particular in such a way that one or both axial ends of the centering part 21 have a receptacle for the balancing weight 22, 23.

The balancing weight 22, 23 is preferably firmly/non-positively (press-)connected to the centering part 21 by a press fit/connection, in particular in such a way that the centering part 21 is rotationally fixed to the balancing weight 22, 23 and/or via the balancing weight 22, 23 is connected to the rotor shaft 19.

It is consequently preferred that the magnet 20 is connected to the rotor shaft 19 in a non-rotatable/non-positive manner exclusively indirectly via the centering part 21 and the balancing weight 22, 23.

In the illustrated embodiment, the balancing weight 22, 23 is pressed at least partially axially or at the end into the centering part 21 or the centering part 21 is pressed at least partially axially or at the end onto the balancing weight 22, 23. However, it is also possible for the centering part 21 to be pressed at least partially axially or at the front into the balancing weight 22, 23 or for the balancing weight 22, 23 to be pressed at least partially axially or at the front onto the centering part 21. In particular, the balancing weight 22 , 23 can have or form an axial receptacle for the centering part 21 .

As already explained, the electric motor 1 preferably has a first balancing weight 22 and a second balancing weight 23, preferably with the balancing weights 22, 23 being designed as separate components. However, it is also possible for the first balancing weight 22 to be formed in one piece with the rotor shaft 19 and/or for the second balancing weight 23 to be formed in one piece with the centering part 21 .

The magnet 20 or the centering part 21 is preferably arranged (axially) between the first balancing weight 22 and the second balancing weight 23 . In particular, a first axial end of centering part 21 is non-rotatably connected to first balancing weight 22 by a press fit, and a second axial end of centering part 21 is non-rotatably connected to second balancing weight 23 by a press fit, preferably wherein balancing weights 22, 23 are each at least partially fitted into the centering part 21 are pressed in.

The following is based on the 6 until 10 the structural design of the balancing weight 22, 23 explained in more detail.

6 shows a schematic side view of the balancing weight 22, 23. 7 shows a perspective view of the balancing weight 22, 23.

The balancing weight 22, 23 is preferably made in one piece and/or made of metal such as copper, lead, zinc, nickel, iron, tin and/or aluminum. The balancing weight 22, 23 is particularly preferably made of a copper-zinc alloy with lead.

As already explained, the balancing weight 22, 23 is preferably at least essentially ring-shaped or designed as a (circular/closed) ring, preferably with the inner surface 22A, 23A being at least essentially circular-cylindrical. In particular, the inner profile or the inner diameter of the balancing weight 22, 23 along the axis of rotation A remains the same or is constant.

The balancing weight 22, 23 has a jacket or outer surface 22B, 23B, preferably with the jacket or outer surface 22B, 23B being of stepped design. In particular, the (outer) profile or the outer diameter of the balancing weight 22, 23 changes over the height of the balancing weight 22, 23 or along the axis of rotation / symmetry A. However, it is also possible that the balancing weight 22, 23 over the Height of the balancing weight 22, 23 or along the axis of rotation / symmetry A has a constant (outer) profile or a constant outer diameter.

The balancing weight 22, 23 preferably has a base 22C, 23C and/or a pin 22D, 23D, in particular the balancing weight 22, 23 and the centering part 21 being formed by pressing the pin 22D, 23D into the centering part 21, in particular the receptacle of the centering part 21, are press-connected to each other.

The base 22C, 23C and the pin 22D, 23D preferably have a different outer contour or a different outer profile and/or a different (maximum) outer diameter.

The base 22C, 23C, in particular the lateral surface of the base 22C, 23C, is preferably of at least essentially circular-cylindrical design.

Preferably, the (maximum) outside diameter of the base 22C, 23C is larger than the (maximum) outside diameter of the spigot 22D, 23D.

The (outside) profile or the outside surface is preferably 22B, 23B of the balancing weight 22, 23 at least in an axial section non-circular or not circular-cylindrical.

In particular, the pin 22D, 23D or the outer surface of the pin 22D, 23D is non-circular or not circular-cylindrical.

Particularly preferably, the balancing weight 22, 23, in particular the (outer) profile or the lateral or outer surface 22B, 23B of the balancing weight 22, 23 or the pin 22D, 23D, is at least essentially polygonal or embodied as polygonal-cylindrical or hypotrochoid-shaped or hypotrochoid-cylindrical, as will be explained in more detail below.

The balancing weight 22, 23 preferably has a (first) pressing surface 22E, 23E and the centering part 21 has a (second) pressing surface 21E, preferably with the centering part 21 and the balancing weight 22, 23 - in particular exclusively - via the pressing surfaces 21E, 22E, 23E (radial) are (press) connected to each other.

The pin 22D, 23D of the balancing weight 22, 23 preferably has or forms the (first) pressing surface 22E, 23E.

In the illustrated embodiment, the (first) pressing surface 22E, 23E is formed as part of the jacket or outer surface 22B, 23B of the balancing weight 22, 23 or the pin 22D, 23D. In particular, the lateral or outer surface 22B, 23B of the balancing weight 22, 23 has or forms the pressing surface 22E, 23E.

The inner surface 21A of the centering part 21 preferably has or forms the (second) pressing surface 21E.

In principle, however, other solutions are also possible, in particular in which the centering part 21 is at least partially pressed into the balancing weight 22 , 23 or the balancing weight 22 , 23 is pressed onto the centering part 21 .

For example, the inner surface 22A, 23A of the balancing weight 22, 23 can have or form the (first) pressing surface 22E, 23E and the outer surface 21B of the centering part 21 the (second) pressing surface 21E.

As already explained at the outset, the present invention provides that the centering part 21 and the balancing weight 22, 23, in particular the pressing surfaces 21E, 22E, 23E, are press-connected to one another only in sections in the circumferential direction or press radially against one another and/or in sections radially in the circumferential direction are spaced apart.

Preferably, one of the pressing surfaces 21E, 22E, 23E, in particular the first pressing surface 22E, 23E, or the profile of one of the pressing surfaces 21E, 22E, 23E, in particular the first pressing surface 22E, 23E (in a top view of the balancing weight 22, 23 or non-round and/or at least essentially polygonal or polygonal-cylindrical or hypotrochoidal or hypotrochoidal-cylindrical in the direction of the axis of rotation A).

In the illustrated embodiment, the (first) pressing surface 22E, 23E of the balancing weight 22, 23 or the profile of the (first) pressing surface 22E, 23E (in a plan view of the balancing weight 22, 23 or in the direction of the axis of rotation A) is non-circular and /or at least essentially polygonal or polygonal-cylindrical or hypotrochoidal or hypotrochoidal-cylindrical and the (second) pressing surface 21E of the centering part 21 or the profile of the (second) pressing surface 21E of the centering part 21 is at least essentially round and/or - in a plan view or in a view parallel to the axis of rotation—circular or circular-cylindrical. In principle, however, solutions are also possible in which the (second) pressing surface 21E of the centering part 21 or the profile of the (second) pressing surface 21E is non-round and/or at least essentially polygonal or polygonal-cylindrical or hypotrochoidal or hypotrochoidal-cylindrical. In such an embodiment, the (first) pressing surface 22E, 23E of the balancing weight 22, 23 is preferably at least essentially circular-cylindrical.

It is preferred that one of the pressing surfaces 21E, 22E, 23E, in particular the (first) pressing surface 22E, 23E of the balancing weight 22, 23, has several, in particular three, (separate) pressing sections 22F, 23F or by several, in particular three ( separate) pressing sections 22F, 23F is formed, preferably with the pressing sections 22F, 23F being press-connected to the opposite pressing surface 21E, 22E, 23E, in particular the (second) pressing surface 21E of the centering part 21, and/or the areas between the pressing sections 22F, 23F are spaced (radially) from the opposite pressing surface 21E, 22E, 23E, in particular the (second) pressing surface 21E of the centering part 21 .

The pressing surface 22E, 23E is preferably at the greatest distance from the axis of rotation A at the pressing sections 22F, 23F.

In other words: the outer radius of the balancing weight 22, 23 preferably varies, esp Special of the pin 22D, 23D or the pressing surface 22E, 23E, in the circumferential direction.

The centering part 21 and the balancing weight 22, 23 are preferably radially (press-)connected to one another exclusively via the pressing sections 22F, 23F.

The pressing sections 22F, 23F are preferably spaced apart from one another in the circumferential direction, in particular arranged offset from one another by 120° and/or distributed uniformly over the circumference of the balancing weight 22, 23.

The pressing sections 22F, 23F are preferably arranged in an attachment plane orthogonal to the axis of rotation A.

The pressing sections 22F, 23F are preferably formed by the (rounded) corners of the polygonal or hypotrochoidal profile of the pressing surface 22E, 23E or of the balancing weight 22, 23, in particular of the pin 22D, 23D. In principle, however, it is also possible for the pressing sections 22F, 23F to be formed by a star-shaped profile or by a projection in each case. In particular, the areas between the pressing sections 22F, 23F can be recessed.

8th shows a schematic view of a proposed hypotrochoidal profile. 9 shows a schematic plan view of the balancing weight 22, 23 with a hypotrochoidal profile.

However, the pressing surface 21E, 22E, 23E, in particular the profile of the pressing surface 21E, 22E, 23E, can also be at least essentially polygonal or polygonal-cylindrical with preferably rounded corners, in particular at least essentially triangular with rounded corners.

The term "hypotrochoid" or "hypotrochoid-shaped" in the sense of the present invention is preferably to be understood as meaning a profile or a closed curve that describes a point in a first, smaller circle if the first, smaller circle is within a second, larger one circle unrolls.

How in particular 8th As illustrated, a hypotrochoid or hypotrochoid profile preferably has a radius r that changes in the circumferential direction and/or changes several times from a minimum radius r _min to a maximum radius r _max .

In particular, the (closed) curve of a hypotrochoid or a hypotrochoid profile lies in a circular ring with an inner radius and an outer radius, the inner radius corresponding to the minimum radius r _min and the outer radius to the maximum radius r _max .

The term “hypotrochoid-cylindrical” or “hypotrochoid-cylindrical surface” in the context of the present invention is preferably to be understood as meaning the lateral surface of a cylinder which has a hypotrochoid as the base surface or a hypotrochoid-shaped base surface.

The term “polygon-cylindrical” or “polygon-cylindrical surface” in the context of the present invention is preferably to be understood as meaning the lateral surface of a cylinder which has a polygon, for example in the form of a triangle with rounded corners, as the base or a polygon-shaped base.

The term “circular-cylindrical” or “circular-cylindrical surface” in the context of the present invention is preferably to be understood as meaning the lateral surface of a cylinder which has a circle as its base or a circular base.

It is therefore preferred that one of the pressing surfaces 21E, 22E, 23E, in particular the first pressing surface 22E, 23E, is the outer surface of a cylinder with a polygon, in particular a triangle, or a hypotrochoid as the base.

The other of the pressing surfaces 21E, 22E, 23E, in particular the second pressing surface 21E, is preferably the outer surface of a cylinder which has a circle as its base.

The profile or the contour of one of the pressing surfaces 21E, 22E, 23E, in particular the first pressing surface 22E, 23E, is (in a plan view of the balancing weight 22, 23 or in the direction of the axis of rotation A) therefore preferably non-circular and/or at least in Substantially polygonal, in particular triangular (with rounded corners), or hypotrochoidal.

The profile or the contour of one of the pressing surfaces 21E, 22E, 23E, in particular the second pressing surface 21E, is therefore preferably round and/or at least substantially (in a top view of the balancing weight 22, 23 or in the direction of the axis of rotation A). formed circular.

The balancing weight 22, 23 preferably has an inner chamfer 22G, 23G and/or an outer chamfer 22H, 23H in order to prevent the balancing weight 22, 23 from being pressed onto the rotor shaft 19 or the balancing dish 22, 23 from being pressed into the centering part 20 to facilitate or to prevent tilting of the components.

Due to the non-round pressing surface 22E, 23E, the width of the outer chamfer 22H, 23H varies in the circumferential direction of the balancing weight 22, 23, such as in particular 6 , 7 and 10 illustrate.

The proposed method for producing the electric motor 1 is described below in particular with reference to FIG 4 and 5 explained in more detail.

The magnet 20 is preferably introduced into the centering part 21, in particular pressed in, particularly preferably in such a way that the magnet 20 is connected to the centering part 21 in a rotationally fixed or non-positive manner and/or the outer surface 20B of the magnet 20 is connected in particular to the entire surface of the inner surface 21A of the centering part 21 applied.

It is preferable for the magnet 20 to be arranged at least essentially in the center of the centering part 21 and/or for the centering part 21 to protrude beyond the magnet 20 in the axial direction, preferably in such a way that a receptacle for the balancing weight 22 or 23 is formed at the axial ends will.

During assembly, the magnet 20 and the centering part 21 are preferably used as a preliminary assembly. In particular, the magnet 20 and the centering part 21 are pushed together as a subassembly onto the rotor shaft 19 and/or the balancing weight 22, 23.

The balancing weight 22, 23 is preferably pushed onto the rotor shaft 19, in particular the first press fit 19C, and/or connected to the rotor shaft 19 in a rotationally fixed manner, in particular by frictional locking.

Preferably only then is the centering part 21 pushed onto the rotor shaft 19 with the magnet 20 and/or press-connected to the balancing weight 22, 23, in particular the pin 22D, 23D. In principle, however, it is also possible for the balancing weight 22, 23 to first be connected to the centering part 21 and then for the centering part 21 to be pushed onto the rotor shaft 19 together with the balancing weight 22, 23, in particular as a preliminary assembly.

Optionally, an adhesive layer is applied to the rotor shaft 19, in particular the adhesive surface 19E, and/or the inner surface 20A of the magnet 20 and/or the magnet 20 is glued to the rotor shaft 19, in particular the adhesive surface 19E.

It is preferred that the balancing weight 22, 23, in particular the pin 22D, 23D, is/is not completely or only partially pressed into the centering sleeve 21, in particular such that the balancing weight 22, 23, in particular the base 22C, 23D, does not rest axially on the centering part 21 and/or the balancing weight 22, 23 is only connected radially to the centering part 21, as in particular in 5 illustrated.

In this way, possible tension is reduced.

As already explained, two balancing weights 22, 23 are preferably used.

After the centering part 21 has been attached or aligned on the first balancing weight 22, the second balancing weight 23 is particularly preferably pushed onto the rotor shaft 19, in particular the second press fit 19D, and/or pressed into the free receptacle of the centering part 21, preferably in such a way that the centering part 21 is arranged with the magnet 20 between the first balancing weight 22 and the second balancing weight 23 .

However, it is also possible for the second balancing weight 23 to be formed in one piece with the centering part 21 . For example, the second balancing weight 23 can form an axial end or a bottom of the centering part 21 .

Preferably, the second balancing weight 23, in particular the peg 23D of the second balancing weight 23, is also pressed only partially or not completely into the centering part 21, in particular in such a way that the second balancing weight 23, in particular the base 23C of the second balancing weight 23, does not come into contact axially the centering part 21 rests and / or the balancing weight 23 is only radially connected to the centering part 21.

In this way, the magnet 20 is centered or aligned relative or coaxially to the rotor shaft 19, with any tension and a resulting bending of the rotor shaft 19 during operation of the electric motor 1 being reduced or be avoided.

The rotor 8 produced in this way is then preferably balanced, in particular using balancing methods known from the prior art, for example in balancing benches or balancing machines, in particular material being removed from the balancing weight 22, 23 by drilling, grinding and/or milling.

The preferably balanced rotor 8 is then inserted into the stator 9 and mounted in the housing 10 via the bearings 17 , 18 .

The pressing surface 22E, 23E, 21E, in particular the pressing surface 22E, 23E of the balancing weight 22, 23, is preferably produced at least partially by out-of-round turning, in particular polygonal or polygon turning, in particular such that the pressing surface 22E, 23E, 21E, in particular the Pressing surface 22E, 23E of the balancing weight 22, 23 (in a plan view of the balancing weight 22, 23 or in the direction of the axis of rotation A) has a non-round profile, in particular an at least essentially polygonal or hypotrochoidal profile, or at least essentially polygonal-cylindrical or is hypotrochoid cylindrical.

In the case of eccentric turning, the tool is moved periodically in addition to the workpiece and as a function of the movement of the workpiece. In this way, non-round, such as polygonal or hypotrochoidal, contours can be produced by turning (out-of-round turning). This enables a particularly cost-effective manufacturing process.

Individual aspects, features and/or method steps of the present invention can be implemented independently, but also in any combination and/or order.

Reference List

1

electric motor

2

fan

3

housing (blower)

4

impeller

5

diffuser

6

blades

7

vanes

8th

stator

9

rotor

10

housing (stator)

11

Wash

12

magnetic core

13

circuit board

14

bracket

15

First housing part

16

Second housing part

17

First camp

18

Second camp

19

rotor shaft

19A

First camp seat

19B

Second camp seat

19C

First press fit

19D

Second press fit

19E

adhesive surface

20

magnet

20A

inner surface (magnet)

20B

outer surface (magnet)

21

centering part

21A

inner surface (centering part)

21B

outer surface (centering part)

21E

pressing surface (centering part)

22

First balancing weight

22A

Inner surface (1st balancing weight)

22B

Outer surface (1st balancing weight)

22C

Socket (1st balancing weight)

22D

Pin (1st balancing weight)

22E

1. pressing surface (1. balancing weight)

22F

Press section (1st balancing weight)

22G

Inner bevel (1st balancing weight)

22H

Outer bevel (1st balancing weight)

23

Second balance weight

23A

Inner surface (2nd balancing weight)

23B

Outer surface (2nd balancing weight)

23C

Socket (2nd balancing weight)

23D

Pin (2nd balancing weight)

23E

Pressing surface (2nd balancing weight)

23F

pressing section (2nd balancing weight)

23G

Inner bevel (2nd balancing weight)

23H

Outer bevel (2nd balancing weight)

A

axis of rotation

right

radius

rmin

Minimum radius

rmax

Maximum Radius

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102017122466 A1 [0005]

Claims (11)

Electric motor (1), in particular for a fan (2), with a stator (8) and a rotor (9), the rotor (9) being rotatable about an axis of rotation (A) relative to the stator (8), the rotor (9) has a rotor shaft (19), a magnet (20), a centering part (21) for the magnet (20) and a balancing weight (22, 23), the balancing weight (22, 23) being non-rotatably connected to the rotor shaft (19 ) and wherein the centering part (21) is non-rotatably connected to the balancing weight (22, 23) by a press fit, characterized in that the centering part (21) and the balancing weight (22, 23) are press-connected to one another only in sections in the circumferential direction . electric motor after claim 1 , characterized in that the balancing weight (22, 23) has a first pressing surface (22E, 23E) and the centering part (21) has a second pressing surface (21 E), the centering part (21) and the balancing weight (22, 23) over the pressing surfaces (22E, 23E, 21E) are press-connected to one another and/or the pressing surfaces (22E, 23E, 21E) only press radially against one another in sections in the circumferential direction. electric motor after claim 2 , characterized in that one of the pressing surfaces (22E, 23E, 21 E), in particular the second pressing surface (21 E), is at least essentially circular-cylindrical. electric motor after claim 2 or 3 , characterized in that one of the pressing surfaces (22E, 23E, 21E), in particular the first pressing surface (22E, 23E), is non-circular and/or at least essentially polygonal or polygonal-cylindrical or hypotrochoidal or hypotrochoidal-cylindrical. Electric motor according to one of claims 2 until 4 , characterized in that one of the pressing surfaces (22E, 23E, 21E), in particular the first pressing surface (22E, 23E), has several, in particular three, pressing sections (22F, 23F) or by several, in particular three, pressing sections (22F, 23F ) is formed, preferably wherein the pressing sections (22F, 23F) are press-connected to the opposite pressing surface (22E, 23E, 21E), in particular the second pressing surface (21E), and/or the areas between the pressing sections (22F, 23F) to the opposite pressing surface (22E, 23E, 21E), in particular the second pressing surface (21E), are spaced. electric motor after claim 5 , characterized in that the pressing sections (22F, 23F) are spaced apart from one another in the circumferential direction, in particular arranged offset from one another by 120° and/or are distributed uniformly over the circumference. Electric motor according to one of the preceding claims, characterized in that the magnet (20) is pressed at least partially, preferably completely, into the centering part (21) and/or in particular glued to the rotor shaft (19) on the inside. Electric motor according to one of the preceding claims, characterized in that the balancing weight (22, 23) has a pin (22D, 23D) and the centering part (21) has a receptacle for the pin (22D, 23D), the balancing weight (22, 23 ) and the centering part (21) are press-connected to one another by pressing the receptacle onto the pin (22D, 23D). electric motor after claim 8 , characterized in that the pin (22D, 23D) has or forms the first pressing surface (22E, 23E) and the receptacle has or forms the second pressing surface (21E). Electric motor according to one of the preceding claims, characterized in that the rotor (9) has an additional balancing weight (22, 23), the balancing weights (22, 23) being of identical design and/or the centering part (21) between the balancing weights (22 , 23) and/or is non-rotatably connected to the balancing weights (22, 23) by a press fit. Method for producing an electric motor (1), in particular according to one of the preceding claims, wherein the electric motor (1) has a rotor shaft (19), a magnet (20), a centering part (21) for the magnet (20) and a balancing weight (22, 23), wherein the balancing weight (22, 23) is at least partially non-circular turning is processed in such a way that the balancing weight (22, 23) has a non-circular, in particular at least essentially polygonal-cylindrical or hypotrochoidal-cylindrical, pressing surface (22E, 23E) for the centering part (21), and the balancing weight (22, 23) being press-connected to the centering part (21) via the pressing surface (22E, 23E).

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