Electric drive motor, especially for use as a lifting motor for an elevator system

Abstract

Drive motor (1), - which is designed as a lifting motor for an elevator system, with - a stator (2) having a stator winding (4) for generating a rotating magnetic field, which is inserted into slots (9) of the stator (2), and - a rotor (3) rotatably mounted about a rotational axis (6), which carries a plurality of permanent magnets (5) and is designed as an internal rotor, - wherein the axis of rotation (6) defines a radial direction R in an xy-radial plane perpendicular to the axis of rotation, - wherein the permanent magnets (5) extend predominantly in the radial direction R and - wherein the rotor (3) forms spokes (7) extending along the radial direction R, which define magnet pockets (8) in the circumferential direction of the rotor (3), into which the permanent magnets (5) are inserted, characterized by - that the permanent magnets (5) are designed as ferrite magnets.

Description

[0001] The invention relates to an electric drive motor, which can be used in particular as a lifting motor for an elevator system (and thus can deliver a minimum torque of 50 Nm). The drive motor / lifting motor comprises a stator having a (preferably three-phase) stator winding for generating a rotating magnetic field, the stator winding being inserted in slots of the stator. The stator winding can be configured as a toothed coil winding or as a distributed winding and / or, in particular, be designed to operate the drive motor with a three-phase electric drive current. Furthermore, the drive motor has a rotor rotatably mounted about an axis of rotation, which carries a plurality of permanent magnets. Here, the rotor is designed as an internal rotor, and the said axis of rotation (z-axis) defines a radial direction R in an xy-radial plane, which runs perpendicular to the axis of rotation.The permanent magnets extend predominantly in the radial direction R, and the rotor forms spokes running along the radial direction R, each of which, in a circumferential direction of the rotor, defines magnet pockets into which the permanent magnets are inserted.

[0002] The stator of the drive motor can hold a number of PZ S at magnetic poles of PZ S = 2p S trains, with p S The number of pole pairs of the stator that form when a corresponding current is applied. The stator has a number N for the electromagnetic generation of these pole pairs. N at slots. The magnetic flux generated by the stator winding can be guided, at least partially, through (especially tooth-shaped) magnetic flux conductors of the stator.

[0003] Such drive motors are already well-known in the form of elevator motors and are frequently designed as permanent magnet synchronous machines (PMSM). For use as a lifting motor in an elevator system, it is crucial that the drive motor can reliably generate sufficient torque (typically at least 50 Nm) over a wide temperature range when starting the motor, i.e., at low rotor speeds, to move an elevator car smoothly and without jerking or disturbing noise (e.g., due to vibrations).

[0004] Current state-of-the-art lifting motors are dominated by permanent magnets based on an iron alloy containing significant proportions of rare earth elements, particularly samarium, neodymium, praseodymium, terbium, gadolinium, and dysprosium. Rare earth elements (RE) generally include lanthanum and the elements following lanthanum (La) in the periodic table: cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu), including the chemically similar element yttrium (Y). Dysprosium is used, for example, to give neodymium-iron-boron magnets higher temperature resistance.Certain rare-earth magnets (SE magnets) based on rare earth elements, primarily neodymium-iron-boron (NdFeB; typical composition: 29–32 wt% neodymium, 64–68 wt% iron, and 1.1–1.2 wt% boron) and samarium-cobalt (SmCo; e.g., 36 wt% samarium and 64 wt% cobalt), are considered the strongest technically available permanent magnets and have enabled the development of new technologies, particularly in wind turbines and hybrid vehicles. Compared to conventional ferrite magnets (which may also contain some SE) and aluminum-nickel-cobalt magnets, such (strong) SE magnets allow for significantly higher coercive field strengths and higher remanent flux densities. The maximum energy product (BH) is also typically higher. maxThe performance of SE magnets is approximately ten times higher than that of ferrite or AlNiCo magnets. However, global resources of SE, particularly samarium, neodymium, praseodymium, terbium, gadolinium, and dysprosium, are limited. Therefore, there is a fundamental desire to design high-performance elevator motors with permanent magnets that do not contain SE, or only in very small quantities, or at least only those SEs that remain readily available, such as lanthanum.

[0005] Furthermore, spoke designs of rotors of an electric motor, as described at the beginning, in which the permanent magnets are no longer arranged on the outside of the rotor, i.e. in the air gap between rotor and stator, but radially inside the rotor, more precisely in respective pockets of the rotor, are also generally known.

[0006] Starting from this prior art, the invention is based on the objective of providing a high-performance drive motor for use as a lifting motor for an elevator system, wherein the drive motor should be inexpensive and reproducible and should also have high electrical efficiency.

[0007] To solve this problem, the features of claim 1 are provided according to the invention for a drive motor. In particular, it is thus proposed according to the invention, to solve the problem in a drive motor of the type mentioned at the outset, that the permanent magnets are designed as ferrite magnets. A ferrite magnet can be understood here to be, in particular, ferrimagnetic ceramic materials made of the iron oxide hematite (Fe₂O₃) and / or magnetite (Fe₃O₄), and optionally other metal oxides. The chemical composition of ferrites can be described by the general formula MeO-Fe₂O₃ = MeFe₂O₄, where Me represents the metals nickel (Ni), zinc (Zn), manganese (Mn), cobalt (Co), copper (Cu), magnesium (Mg), or cadmium (Cd) in soft magnetic ferrites, and barium (Ba), strontium (Sr), or cobalt (Co) in hard magnetic ferrites. Such ferrite magnets can also contain certain proportions of rare earth elements, in particular lanthanum.While ferrite magnets do not offer the high energy densities of strong SE magnets, they are significantly cheaper and more readily available.

[0008] A drive motor according to the invention can be designed as an electric permanent magnet synchronous machine (PMSM). With the aid of a suitable frequency converter, the drive motor can thus be operated with alternating current.

[0009] The ferrite magnets can either be completely free of rare earth elements or contain only small amounts (< 10 wt%) of (readily available) rare earth elements, such as lanthanum. It is advantageous if the ferrite magnets each contain a total rare earth element content of less than 15 wt%, preferably less than 10 wt%. A ferrite magnet suitable for the inventive approach can, for example, have a composition containing > 75% Fe₂O₃ and, in addition, oxides of the elements strontium (Sr), calcium (Ca), silicon (Si), barium (Ba), lanthanum (La), and cobalt (Co).

[0010] To maximize the magnetic flux, it is preferred that the magnetic pockets are completely filled with the magnetic material of the permanent magnets (i.e., not with a non-magnetic material such as air or at least partially with a non-magnetic spacer, as is often the case with previously known designs).

[0011] Along the outer circumference of the rotor, openings can be formed between the spokes, connecting the magnet pockets to the necessary air gap between the rotor and stator. These openings separate each circumferential pole section (formed by the respective spoke) from an adjacent circumferential pole section of the rotor. Each circumferential pole section can have projections on both sides (hereinafter referred to as "retaining projections") against which the permanent magnets bear in a radial direction and are thus held in position when the rotor rotates. Both the magnet pockets and the aforementioned outer circumferential openings, which are both arranged between the spokes of the rotor, can preferably be evenly distributed along the circumference. This ensures a uniform sequence of the rotor's magnetic poles around its outer circumference, which is advantageous for the smooth running of the motor.

[0012] The rotor can be conceptually divided into three radially successive areas in the xy-radial plane, or can form such radial areas: (i) a central area (“near-axis area”). This can be designed as a rotor yoke, which is preferably free of air pockets but may have a central receiving hole. The central area / rotor yoke can thus form a receiving hole for receiving a motor shaft of the drive motor. (ii) a central area in which the permanent magnets extend in a radial direction (e.g. from IUK1 to IUK3 - cf. Fig. 3 or Fig. 5) The central area can be formed by the spokes of the rotor as well as by connecting webs, each of which links a spoke to the central area / rotor yoke. The connecting webs can also be considered part of the respective spoke. (iii) an outer region of the rotor. This is located radially outside and, in particular, forms an outer contour of the rotor extending in the circumferential direction. This outer radial region of the rotor is preferably free of magnets.

[0013] The outer radial section of the rotor can, for example, be formed by the spoke heads of the rotor spokes. These spoke heads then form respective circumferential pole sections of the rotor. Each circumferential pole section, in turn, forms a magnetic pole of the rotor (once the permanent magnets are inserted into the magnet pockets). The outer contour of the circumferential pole sections, and thus of the rotor, can preferably follow a circular line (where this circular line then defines the outer diameter of the rotor). This ensures, in particular, that (apart from openings between the circumferential pole sections) the radial width of an air gap between the rotor and stator in the region of the circumferential pole sections along the circumference of the rotor remains constant.In other words, the rotor blades do not have a polygonal outer contour, but rather an outer contour that follows a circular line (with the exception of the openings between the spokes that cause further air gaps).

[0014] As mentioned, air gaps are preferably formed along the circumferential direction between the individual spoke heads of the rotor. These air gaps can have a length g in the circumferential direction that is smaller than the magnet width M (g < M) and, particularly preferably, also smaller than the spoke width S (g < S).

[0015] The rotor can preferably be (entirely) constructed from a stack of metal laminations (so-called rotor laminations, for example, each with a thickness of approximately 0.5 mm) that follow one another in the axial z-direction and each run parallel to the radial plane. To reduce magnetic stray losses, previously known rotor designs often use non-magnetic components (such as a non-magnetic ring) as parts of the rotor. The inventive design of the rotor using single-piece rotor laminations that form the lamination stack has, compared to such previously known solutions (which show a modular rotor structure and in which the rotor yoke is often made of a non-magnetic material), the disadvantage that stray fluxes can occur in the rotor yoke.However, according to the invention, such stray losses can be effectively reduced by a delicate design of the connecting webs, because magnetic saturation then occurs in these areas. Therefore, according to the invention, the rotor laminations from which the laminated core is formed are each made entirely of magnetic material (for example, steel).

[0016] Furthermore, it is preferred if the rotor laminations each form the entire rotor cross-section (i.e., in particular the aforementioned radial areas: central, near-axis area; middle area; and outer area). Such rotor laminations can be obtained, for example, by punching or laser cutting. The single-piece formation of the rotor cross-section by the respective rotor lamination has the significant advantage of simplified assembly, as there is no need for the complex joining of multiple parts. Moreover, transitions between the aforementioned radial areas (especially in the area of ​​the connecting webs between the central and middle areas) can be designed to be very delicate without compromising the mechanical strength of the rotor.The one-piece design of the rotor laminations thus allows for higher mechanical strength than with multi-piece designs, enabling the transmission of very high torques without compromising the stability of the rotor.

[0017] Each rotor lamination can have corresponding recesses (e.g., laser-cut) to form the magnet pockets. The rotor laminations can also be held together by axially extending screws. The magnet pockets can thus extend axially and radially through the lamination stack. The rotor laminations can therefore be connected to each other, for example, by axial screws. To suppress magnetic leakage, an end plate made of a non-magnetically conductive material, such as stainless steel, can be provided on each (axial) outer surface of the rotor. Such an end plate can also provide the lamination stack with additional mechanical stability, especially if the respective end plate is continuous without interruptions at the outermost radial area (near the air gap).The end plate can thus bridge gaps between the spoke heads of the rotor and mechanically connect them. In particular, this ensures that the delicate spokes, which are only connected to the rotor yoke by the thin web, do not bend.

[0018] In the spoke design according to the invention, the field lines emanating from the individual permanent magnets run radially, but also—in a radially outer region of the rotor—circumferentially. The magnetic poles of the permanent magnets are oriented with their north-south pole alignment (preferably strictly) in the circumferential direction of the rotor. In this way, a sequence of magnetic poles (N, S, N, S, ...) alternating in the circumferential direction of the rotor is formed on the outer surface of the rotor, i.e., in the region of the air gap between the rotor and stator. These magnetic poles of the rotor ultimately set the rotor in rotation by interacting with the rotating magnetic field generated by the stator winding.

[0019] According to the invention, the problem can also be solved by further advantageous embodiments according to the dependent claims, which are described in detail below: The invention recognizes that for the desired lifting motor application, where high acceleration torques must be achieved, it is necessary to maximize the magnetic energy density in the air gap. A high magnetic flux in the rotor is advantageous for this purpose, and this can be achieved if the spokes are designed with a delicate profile and thus occupy only a limited angular range, because this leads to the desired magnetic saturation effects in the area of ​​these spokes. Accordingly, it can be provided that the spokes in a radial region in which the permanent magnets are arranged (this concerns – along the radial axis R – that region of the rotor which the permanent magnets occupy along the radial direction R, for example from IUK1 to IUK3 – see Figure 1). Fig. 6), each with reference to a center point M of the rotor, occupy an angular range α for which: α < 18°, preferably α < 15° or even α < 10° and at very high pole numbers of PZ R > 22 possibly even α < 8°. The angular range can be measured at the radially outer end of the respective magnet (i.e., at the level of IUK3 - cf. Fig. 1) can be determined, neglecting the aforementioned retaining projections, which merely serve to hold the permanent magnets in place when the rotor rotates. If α < 15°, the circumferential width of the permanent magnets M can be smaller than the spoke circumferential width S (M < S); for rotor pole numbers of PZ R However, > 22 can typically be: M > S.

[0020] Alternatively, the angular range can also be determined according to the following (empirical) quadratic equation as a function of the number of poles PZ. R of the rotor (the number N) PM its permanent magnets correspond to PZ R = NPM ) should be reasonably limited: α<0.0125°×PZR2−0.925°×PZR+22.5°

[0021] With such a design, the spoke circumference S can always be smaller than the circumference of the permanent magnets M, so that: S < M (as will become clear from the figures).

[0022] Each of the rotor spokes can form two straight longitudinal edges as contact surfaces for the permanent magnets. These longitudinal edges of the spokes preferably extend in the xy-radial plane along a respective radially outer region of the respective permanent magnet (adhering to this longitudinal edge).

[0023] To maximize the magnetic energy density in the air gap, it is also advantageous according to the invention if the spokes are connected to the central area of ​​the rotor (rotor yoke), which is free of magnetic pockets, by comparatively narrow connecting webs, because this allows a desired magnetic saturation to be achieved in the area of ​​the webs, thus increasing the field density in the air gap. In principle, it would be advantageous for the same reason to choose comparatively long webs. However, a long web design is critical with regard to the mechanical stability of the rotor. Therefore, a preferred embodiment provides that the spokes of the rotor extend to an inner circumferential circle IUK2 and that the webs are dimensioned as described below. From this inner circumferential circle IUK2, the longitudinal edges described can extend radially outwards.

[0024] The aforementioned connecting webs, which link the spokes of the rotor to a central area of ​​the rotor, can extend radially inwards (beyond the spokes, i.e., starting from IUK2) to an inner circumferential circle IUK1 (which is then smaller than IUK2). The difference between the radii R IUK1 and R IUK2 The two inner circumferential circles IUK1 and IUK2 can thus be understood as a radial length RLS of the connecting webs. In this case, the following can then apply to RLS with respect to a radial extent / length RLM of the permanent magnets (regardless of whether the respective magnet pocket is completely or only partially filled with one or more magnets): RLS = R IUK2 -R IUK1 < 0.18 RLM, preferably: RLS < 0.16 RLM.

[0025] A preferred range of values ​​according to the invention for the ratio R IUK1 / R R (cf.) Fig. 6) is: 0.48 ≤ R IUK1 / R R ≤ 0.55, preferably: 0.50 ≤ R IUK1 / R R ≤ 0.54.

[0026] Provided that the respective magnet completely or almost completely fills the entire magnetic pocket (then: RLM ≈ RLMT, with RLMT being the radial length of the respective magnetic pocket), the following can apply, for example: RLS < 0.16 RLM, preferably: RLS < 0.14 RLM. With a sufficiently large drive motor, RLS < 0.12 RLM may even apply.

[0027] Alternatively, the following can also apply with reference to the radial length of the magnet pockets: RLS < 0.16 RLMT, preferably RLS < 0.14 RLMT, where RLMT is the radial length of the magnet pocket. With a sufficiently large drive motor, RLMT < 0.12 RLM may even apply.

[0028] The permanent magnets can extend radially on the inside to the larger inner circumferential circle IUK2. However, preferred configurations are those in which the permanent magnets also occupy circumferential sections of the rotor that lie along the circumference between the connecting webs. In such a case, the permanent magnets can therefore extend to the smaller inner circumferential circle IUK1 or at least beyond IUK2. As shown in the Fig. As will be shown in Figure 7, it is also possible to provide separate permanent magnets that fill the rotor's receiving pockets, which are arranged circumferentially between the connecting webs.

[0029] The two longitudinal surfaces or longitudinal edges of each spoke can preferably enclose an angle of β < 18°, preferably β < 15° or even β < 14°, in individual cases even β < 13.5°, particularly for a rotor outer diameter of D R= [215 - 300] mm. A particularly preferred range for β is 11.5° < β < 13.5°, which is especially advantageous in combination with a rotor outer diameter of D. R = [200 - 300] mm leads to a high efficiency of the drive motor.

[0030] The magnetization of the permanent magnets is aligned circumferentially according to the spoke concept. In this way, alternating magnetic north and south poles can be formed on the outer surface of the rotor in the circumferential direction, defining the magnetic poles of the rotor and thus its number of poles, PZ. R define. In the spoke design, as mentioned, the number of poles corresponds to PZ. R of the rotor of the number N PM its permanent magnets: PZ R = N PM According to the invention, for high efficiency of the drive motor, it is advantageous if it has a high number of rotor poles PZ. R (PZ R ≥ 20) as well as a high number N Non grooves (N N ≥ 24) in the stator.

[0031] A particularly advantageous embodiment for a small size of a drive motor according to the invention, which can have a delicate spoke design as described herein (with corresponding values ​​for RLS, RLM, α, β etc.), is seen in a size of D R = [130 - 180] mm one rotor pole number PZ R in the range 8 ≤ PZ R ≤ 14. With such a rotor design, the number N can then be N on grooves in the range of 9 ≤ N N ≤ 15 must be selected in the stator.

[0032] Particularly in the case of a larger drive motor, the following can apply, for example, to embodiments according to the invention: PZ R ≤ 36 (in this case, the number of slots can also preferably be N N apply: N N ≤ 48) or PZ R ≤ 32 (in this case, the following may also preferably apply: N N ≤ 40).

[0033] In general, according to the invention, the number N can be N at the stator slots, thus values ​​of N N ≤ 72, or even N N The number of poles should be limited to ≤ 54. This is because, with too high a number of poles (and the resulting high number of slots), the advantages of the spoke design according to the invention can no longer be realized in practice.

[0034] A particularly preferred embodiment for a smaller-sized drive motor according to the invention provides: D R = [130 - 180] mm, PZ R = 10 and N N = 12. In particular, it may also be provided that: α < 18°.

[0035] If, however, the rotor size is D R > 180 mm, so accordingly for a number N PM The following apply to the permanent magnets of the rotor: N PM ≥ 20, preferably the following can apply: N PM ≥ 24 and therefore also PZ R ≥ 20 or PZ R≥ 24. Furthermore, it may be additionally or alternatively provided that the number of slots of the stator N N applies: N N ≥ 24, preferably the following can apply: N N ≥ 28 or even N N ≥ 32.

[0036] In general, designs according to the invention can provide that the number of poles PZ R However, the number of poles is limited at the top (very high pole counts should therefore be avoided) so that the individual spoke does not become too thin and thus prone to breakage. Accordingly, it can be stipulated that: PZ R ≤ 40, PZ R ≤ 36 or even PZ R ≤ 32 (regardless of the size of the drive motor). The smaller the outer diameter of the drive motor and thus of the rotor, the smaller the number of poles PZ must be. R They are chosen to ensure that empirically determined minimum spoke strengths are not undercut, especially in the area of ​​the delicate connecting webs.

[0037] One particularly preferred embodiment, Proto1, provides for a pole number PZ. R of the rotor of PZ R ≥ 28, preferably in combination with a number N N on the slots of the stator of N N ≥ 36, especially PZ R = 28 and N N = 36. The following may also apply: D R > 200 mm.

[0038] Another preferred embodiment, Proto2, which is suitable for larger overall drive motor sizes, provides: PZ R ≥ 30, preferably and N N ≥ 36, especially PZ R = 30 and N N = 36. The following may also apply: D R > 250 mm.

[0039] As a general design rule, the invention proposes a ratio of the number of poles of the rotor PZ. R and a bore diameter D B (This corresponds to the inner diameter of the stator; therefore, with regard to Fig. 1: D B = D R+ 2 LS) from PZ R / D B To select > 0.120. With a bore diameter D B (Stator inner diameter) of 230 mm can, for example, accommodate a rotor pole number of PZ. R = 28 selected; at D B = 250 mm, however, already corresponds to a rotor pole number of PZ R = 30 or PZ R = 32. In the previously described configurations Proto1 and Proto2, for example, a pole number of PZ is possible. R = 28 with a value of D B = 230 mm and a pole count of PZ R = 30 with a value of D B = 290 mm combined.

[0040] Generally speaking, a sensible range of values ​​for the bore diameter D can be B = (D R + 2LS), especially with pole numbers of PZ R ≥ 20, according to the invention as a function of the number of poles of the rotor PZ R can be determined using the following empirical formula: DB>31 / 42×PZR2−12.8×PZR.

[0041] This could result in, for example, the following minimum values ​​for D B Result: 118 mm with PZ R = 24 or 220 mm for PZ R = 28 or 280 mm for PZ R = 30. This formula can of course also be used for a desired size D S and thus D B a sensible number of poles PZ R for the rotor. The smaller the size of the drive motor, the smaller the number of poles PZ must be, according to the empirical approach above. R be elected.

[0042] According to the invention, the efficiency of the drive motor can also be increased by shifting the air gap radially outwards. Accordingly, a ratio between a maximum outer diameter D can be achieved. R of the rotor and a maximum outer diameter D S of the stator: D R / D S > 0.70, preferably: D R / D S> 0.75. This can also increase the magnetic flux, because the permanent magnets extend further radially outwards the larger the ratio D. R / D S The air gap between the rotor and stator with radial extension LS should be chosen to be as small as possible; taking into account manufacturing tolerances, it can be in the range of less than 0.8 mm.

[0043] A particularly preferred embodiment provides a ferrite rotor design: Accordingly, the permanent magnets can be designed as ferrite magnets, preferably with a magnetic flux density of at least 0.35 T or even at least 0.38 T.

[0044] Each radially outer end of the respective permanent magnet can be spaced radially R away from the outer circumference of the rotor by a distance d (so that the permanent magnets are offset radially inwards). This distance d can be chosen in the range of [2.50 - 5.0] mm; this represents a suitable technical compromise: If d is larger, the magnetic flux is unnecessarily reduced; if d is smaller, there is a risk of demagnetization of the radially outermost areas of the respective permanent magnet in certain operating conditions of the motor. This distance d (= radial height of the spoke heads of the rotor spokes) can correspond to a radial extension of the circumferential pole sections (= spoke head) or the outer radial area of ​​the rotor, as introduced above. The advantage of using ferrites (which can be hard or soft magnetic) is that they only require approximately...They cost one-tenth of the material costs compared to rare earth permanent magnets (SE magnets) and are also more readily available.

[0045] However, a significant challenge then lies in designing the drive motor in such a way that sufficient torque can be generated despite the considerably lower flux density B of the ferrites, particularly during start-up. According to the invention, the lower flux density of permanent magnets (especially those completely free of rare earth elements) can, in principle, be compensated for by an adapted spoke design. Therefore, especially when using ferrite magnets, a delicate spoke design is crucial according to the invention to compensate for the lower magnetic flux density compared to rare earth magnets.Therefore, a preferred embodiment provides that the respective magnet width M of the permanent magnets, which can be measured circumferentially as a circumferential length at the radially outermost point of the respective permanent magnet, is larger than the respective spoke width S, which is also measured circumferentially as a circumferential length at the height of the radially outermost point of the respective permanent magnet.

[0046] Alternatively or additionally to the design criterion M > S, it can also be provided that an angular region γ occupied by the respective permanent magnet at its radially outermost end in the radial plane (with respect to the center point M) is larger than an angular region α occupied by a spoke adjacent to this permanent magnet in the radial plane at the same radial height, in each case with respect to the center M of the rotor. The spokes of the rotor, each occupying an angular region α, can form spoke heads at their respective radially outer ends, which project beyond this angular region α (these are the "retaining projections"). The spoke heads can thus occupy an angular region δ > α.

[0047] Each spoke head can thus form a retaining projection at its left and right ends with a circumferential length u (measured on the radially inner side of the retaining projection opposite the permanent magnet). These retaining projections can act as stops, limiting the permanent magnets in the radial direction and thus absorbing centrifugal forces that arise during rotation of the rotor.

[0048] The invention also provides preferred embodiments with regard to the radial arrangement of the magnets and their (respective) radial extent RLM: The permanent magnets can each extend in the radial direction over at least a radial length RLM, for which, in relation to the outer diameter D, R = 2R R of the rotor or its radius R R The following applies: RLM ≥ 41% R R Preferably, RLM ≥ 42% R can apply. R and especially preferred RLM ≥ 43% R R .

[0049] Additionally or alternatively, the following may also apply: RLM ≤ 49% R R , preferably RLM ≤ 48% R R and especially preferred RLM ≤ 47% R R. A particularly preferred range of values ​​for the RLM / R ratio R In particular: 43% R R ≤ RLM ≤ 47% R R.

[0050] The magnetic pockets (and thus also the radially inner end of the respective permanent magnet, provided the magnetic pocket is completely occupied by the permanent magnet) can extend to a radial depth RT (measured from the center M of the rotor), for which the following applies: 45% R R < RT < 55% R R , with R R the radius of the rotor up to its outer diameter, preferably: RT < 54% R RThis also optimizes the electrical efficiency of the drive motor when using ferrite magnets, while simultaneously ensuring sufficient mechanical stability of the rotor spokes.

[0051] For a total radial length of the magnetic pockets RLMT (measured from IUK1 to IUK3, which, if the magnetic pockets are completely filled, can also correspond to the radial length of the magnets, so that then: RLM ≈ RLMT) the following can apply: 42% R R < RLMT < 49% R R, The preferred rule is: 43% R R < RLMT < 47% R R.

[0052] As already mentioned, according to the invention it is advantageous if the connecting webs are designed to be narrow in the circumferential direction. Therefore, a preferred embodiment provides that the spokes are connected to a central area of ​​the rotor via connecting webs, this central area preferably being free of air pockets and, in particular, being designed in the form of a solid rotor yoke. Here, the central area of ​​the rotor can form a receiving hole, which can then serve to receive a motor shaft. The permanent magnets preferably extend to an inner circumferential circle IUK1, at which the connecting webs transition into the central area of ​​the rotor in order to maximize the magnetic flux (in this case, the permanent magnets completely fill the magnet pockets). In general, both the connecting webs and the central area of ​​the rotor can thus help to define the magnet pockets of the rotor.

[0053] Preferably, the connecting webs can have a circumferential width b of < 1.80 mm or even < 1.70 mm at their thinnest point. Depending on the size of the drive motor, the circumferential width b can alternatively be limited according to the following empirical formula: b<(2 π RIUK1 / PZR)×0.15 with R IUK1 the radius of the inner circumferential circle IUK1 (measured in mm) up to which the magnetic pockets are guided radially inwards and PZ R the number of poles of the rotor. In such a design, the web width b is therefore less than 15%, or even less than 13%, of the circumferential length segment 2πR corresponding to a pole of the rotor. IUK1 / PZ R of IUK1. In preferred configurations, the said value can even be less than 12.5%.

[0054] The invention also proposes novel geometric shapes for the permanent magnets: For example, one embodiment provides that all the permanent magnets supported by the rotor have a (at least partially or completely) polygonal cross-section with respect to the aforementioned radial plane. Such a shape of the permanent magnets has the advantage of being easy to manufacture.

[0055] Furthermore, it is preferable if at least some or all of the permanent magnets supported by the rotor have a radially inward wedge-shaped region. A wedge shape can be understood here, in particular, as meaning that the magnets, with respect to their cross-section in the xy-radial plane, taper radially inward on one or both sides within the wedge-shaped region. In particular, the magnets can form outer edges in the wedge- or trapezoidal region that extend along the radial direction R.

[0056] The wedge-shaped area can, in particular, have a trapezoidal shape. Here, "trapezoidal shape" refers to both right-angled and non-right-angled trapezoids. Therefore, the wedge-shaped / trapezoidal area of ​​the magnet does not necessarily have to be axially symmetrical with respect to the radial direction; asymmetrical shapes are also possible within the scope of the invention.

[0057] The wedge-shaped / trapezoidal section of the respective magnet can directly abut the aforementioned connecting webs that link the rotor spokes to the central radial section of the rotor. In such a configuration, some or even all of the connecting webs can have a central orientation aligned with the radial direction R. This is advantageous for absorbing centrifugal forces, allowing the connecting webs to be designed with a particularly delicate profile.

[0058] Furthermore, for ease of manufacturing, it is preferable if all of the permanent magnets carried by the rotor have at least a rectangular area in the radial plane.

[0059] Preferably, all permanent magnets of the rotor (regardless of whether one or two different types of magnets are used) follow the cross-sectional shape of the directly adjacent connecting bridges in the radial plane, so that no air pockets form between the permanent magnets and the connecting bridges (but rather the respective magnet pocket located between the connecting bridges is completely filled by the magnet). In other words, the connecting bridges can also define the boundaries of the aforementioned magnet pockets.

[0060] The permanent magnets can preferably correspond in shape to the shape of the associated magnetic pocket, so that the permanent magnets completely fill the magnetic pockets, at least in the middle radial area of ​​the rotor, but preferably overall.

[0061] Furthermore, to avoid air pockets, it is preferable for the permanent magnets to have their radially inner end faces in direct contact with the rotor yoke / central area of ​​the rotor, so that no air pockets (of relevant size) form in this area either. It is understood that due to manufacturing tolerances, some air gaps may still exist between the rotor and the permanent magnets.

[0062] A particularly unusual embodiment of the invention provides that at least two different types of permanent magnets are used in the drive motor. Thus, the permanent magnets of the rotor can comprise two different geometric types, A and B. In other words, the magnet pockets can have different shapes (so that they are designed to accommodate different geometric types of permanent magnets), and the magnet pockets can also overlap / merge into one another – see magnet pockets 8a and 8b in [reference missing]. Fig. 8).

[0063] When using two different types of permanent magnets A and B, it is preferred if one of the two types (e.g. the type that is arranged radially inside, cf. Fig. 8) has a wedge shape on the radial inside (see the Fig. 4-6 and 8). In particular, it may be provided that a type of permanent magnet is arranged radially inside the rotor (cf. type B in Fig. 8), has outer edges that run along the radial direction R in order to achieve the desired wedge shape (cf. Fig. 8).

[0064] In general, when using two types A and B arranged radially one behind the other, it is advantageous and therefore preferred if these are in a common (e.g., two-part, as in the example of the Fig. 8) are arranged in a magnetic pocket. In this way, the two magnets A and B can be in direct contact with each other, which avoids stray losses. At the same time, however, the division into two separate magnets A and B allows for simpler and therefore more cost-effective manufacturing of each magnet.

[0065] When using (at least) two different types A and B of permanent magnets, the types A and B can thus alternate in the circumferential direction (cf. Fig. 6) or types A and B can be arranged one behind the other in the radial direction R (cf. Fig. 7 and Fig. 8) In the latter embodiment, it is advantageous if the radially inner type B then has the aforementioned wedge shape (cf. Fig. 8) All these designs result in an increase in magnetic flux, which is beneficial for the efficiency of the motor, and at the same time ensure sufficient mechanical stability of the one-piece rotor laminations, especially in the area of ​​their delicate webs (cf. Fig. 8).

[0066] One embodiment provides that two different geometry types A and B of permanent magnets are alternately inserted circumferentially into corresponding magnet pockets of the rotor (in this case, each with a different geometry). It is particularly preferred if (with respect to the xy-radial plane) the permanent magnets of one of the two geometry types (e.g., type B in) Fig. 5) have a rectangular cross-sectional shape (since this is easy to manufacture - see the Fig. 4-8) and / or if the permanent magnets are of one of the two types (e.g., the permanent magnets of geometry type A in Fig. 5) have a wedge shape on the radial inner side (see Fig. 4-6). This wedge shape can be realized by a trapezoidal area (as previously explained) (cf. Fig. 4).

[0067] When using two different magnet geometries A and B, it is preferable for a uniform formation of the rotor's magnetic poles if the spoke width S of each spoke, measured at the radial height of the outermost radial point of the respective permanent magnet, is always constant. Furthermore, when using two different geometries, it is also preferred if all permanent magnets of the same type have the same radial extent RLM and are also arranged within the same central region of the rotor (i.e., have no radial offset from each other). With such a configuration, the radial lengths RLM can thus be A and RLM B the two types A and B must be of the same length (as in the example of the Fig. 4).

[0068] For example, the permanent magnets, either all of them, or only those of type A, or only those of type B, can have a chamfer on one or both sides on their radially inner side (i.e., in the area of ​​the connecting webs between the central area of ​​the rotor and the radially outer spokes). Such a chamfer can preferably be designed such that the respective outer edge of the affected permanent magnet runs radially in the area of ​​an associated connecting web. In this way, it can be achieved that the permanent magnets (each) extend to an inner circumferential circle IUK1, at which the connecting webs transition into the central area of ​​the rotor / the rotor center / the rotor yoke.

[0069] A characteristic feature of a rotor design of the drive motor according to the invention can also be a non-radial (i.e., an oblique orientation to the radial direction R) orientation of the connecting webs that connect the spokes to the central area of ​​the rotor. Accordingly, it can be provided that the spokes of the rotor are connected to the central area of ​​the rotor via connecting webs and that a respective mean orientation of one or all of these connecting webs is oblique to the radial direction. For example, the respective orientation can run at an angle of more than 5° to the radial direction R. Depending on the embodiment, it is particularly possible that the orientations of adjacent connecting webs intersect, with the intersection point being located in the central area of ​​the rotor.This design also makes it possible to use easy-to-manufacture types of magnets, thus simplifying production.

[0070] Alternatively, according to a further embodiment, two different geometry types A and B of permanent magnets can be arranged one behind the other in the radial direction R (in particular between each pair of spokes). In such an embodiment, for example, two cuboid geometry types A and B can be used, or geometries that differ more significantly.

[0071] An unusual, yet inventive embodiment provides a geometry of the permanent magnets without a wedge shape, based on two rectangular geometry types A and B of permanent magnets (e.g., as in Fig. (Figure 7 illustrates): Thus, one or all of the rotor's magnet pockets, relative to the radial plane, can have a cross-section comprising two rectangular areas of different sizes. Such a configuration of the magnet pockets can then be combined, in particular, with two cuboid permanent magnets A and B arranged radially one behind the other in the respective magnet pocket. In this case, the radial lengths of the permanent magnets RLM can be A and RLM B They can also differ considerably. It is particularly advantageous if type B is arranged radially inside and type A radially outside, and furthermore: RLM A > 3 RLM B .

[0072] In such a configuration, a radially outer of the two rectangular areas (and thus in particular a first permanent magnet A, as in Fig. 7 (illustrated by way of example) lie against the longitudinal edges of the spokes, while a radially inner of the two rectangular areas of the magnet pocket (i.e., in particular also a radially inner second permanent magnet B - cf. e.g. Fig. 7), is located on connecting webs of the rotor, which, as already explained several times, each connect the spokes to a central area of ​​the rotor.

[0073] According to the invention, it is advantageous if the magnets occupy a high proportion of the existing circumferential circle (IUK1 / IUK2 / IUK3) of the rotor both in the area of ​​the connecting webs and in the area of ​​the outer circumference of the rotor, because this maximizes the magnetic flux, and in particular allows a desired sufficient magnetic saturation to be achieved in the area of ​​the connecting webs (a high magnetic saturation in the area of ​​the connecting webs reduces the leakage flux in the rotor and thus leads to a desired concentration of the magnetic flux in the air gap between stator and rotor, which in turn is favorable for a high power factor) in order to favorably influence the course of the field lines.Therefore, one embodiment proposes that at the radial height of a radially outermost inner circumcircle IUK3, to which the permanent magnets extend, the permanent magnets together comprise at least 50% or at least 51%, or even at least 52% of a respective circumferential length L. IUK3 occupy the inner circumferential circle IUK3. This allows, in particular, the energy density in the gap between rotor and stator to be increased.

[0074] Similarly, particularly if the magnet pockets are completely filled by the respective permanent magnet, it can be provided that at the radial height of the inner circumferential circle IUK1 (where the connecting webs that connect the spokes to the central area of ​​the rotor transition into the central area of ​​the rotor; IUK1 can in particular be the inner circumferential circle to which the permanent magnets extend radially inwards - cf. e.g. Fig. 3 or Fig. 6) the permanent magnets together comprise at least 84% or even at least 86% of the circumferential length L IUK1 occupy the inner circumcircle IUK1.

[0075] At the radial height of the inner circumferential circle IUK2 (where the connecting webs transition into the spokes), the permanent magnets can cover a total of at least 85% or at least 87% of the circumferential length L. IUK2 of the inner circumferential circle IUK2. In such configurations, the magnets are thus very closely spaced along the circumferential direction, resulting in high magnetic saturation in the area of ​​the connecting webs and therefore a desired concentration of magnetic flux in the air gap between the stator and rotor. This, in turn, is advantageous for achieving a high power factor cos φ.

[0076] The design according to the invention can be further improved by providing an axial projection of the permanent magnets beyond the rotor: Accordingly, individual, but preferably all, of the permanent magnets supported by the rotor can project in the axial direction of the rotor's axis of rotation beyond the stator and / or beyond the rotor (i.e., in particular beyond a laminated core forming the rotor). It is preferred that this axial projection is configured on both sides (with respect to the axis of rotation). For example, the aforementioned axial projection can be at least 5 mm on each side of the stator, regardless of the motor's size. In this case, the rotor may not project beyond the stator at all, or at most by 10% of the stator's axial length on each side.With an axial length of 95 mm for the lamination stack forming the rotor, an overhang of 5 mm on each side is sufficient to achieve a significant reduction in the effects of magnetic stray fields and thus a high homogeneity of the magnetic flux in the air gap between rotor and stator.

[0077] The invention will now be described in more detail using exemplary embodiments, but is not limited to these; rather, it is defined in the claims. It shows: Fig. 1 a scaled cross-sectional view of a simulation model which was used for the computer-aided investigation of drive motors according to the invention, wherein only one quadrant is illustrated, Fig. 2 and Fig. 3 partial views of a possible embodiment of a rotor according to the invention as part of a drive motor according to the invention, Fig. 4 another possible embodiment of a rotor according to the invention using two types A and B of different permanent magnets, Fig. 5 another view of the rotor design according to Fig. 4, Fig. 6 a complete cross-sectional view of the rotor design according to Fig. 4 and Fig. 5, Fig. 7 a further partial view of a possible embodiment of a rotor according to the invention using two different types A and B of permanent magnets, both of which are cuboid in shape and finally Fig. 8 another partial view of a possible embodiment of a rotor according to the invention using two different types A and B of permanent magnets.

[0078] The Fig. Figure 1 shows a cross-sectional view along the axis of rotation 6 of a simulation model used to simulate drive motors 1 designed according to the invention, specifically the magnetic field distributions, in order to verify experimental results. The view shows only one quadrant, but the essential parts and basic geometry of the rotor 3 and the stator 2 can be seen from the illustration. As provided in a drive motor 1 according to the invention, the stator 2 has a stator winding 4, which is inserted into a total of 30 slots 9 of the stator 2 and generates a rotating magnetic field when energized.

[0079] In a drive motor 1 according to the invention with a suitable combination of slots and poles of the rotor, this rotating field will cause the rotatably mounted rotor 3 to rotate, because it has a plurality of permanent magnets 5 (in the example of the Fig. 1. It carries a total of 30 magnets. The rotor 3 is designed as an internal rotor, so that an air gap with radial extent LS exists between the rotor 3 and the stator 2 (cf. Fig. 1).

[0080] The presentation of Fig. Figure 1, in which a technically impractical combination of 30 magnets with 30 slots in the stator is combined, serves only to illustrate and define the geometric parameters, so that embodiments according to the invention can be easily derived based on the claims and the general description. In a technically meaningful way, a ratio of N can be used in a drive motor 1 designed according to the invention. N > PZ R be chosen, whereby the other geometry of the in Fig. The rotor shown in 1 can be retained.

[0081] In Fig. 1 The inner circumferential circles IUK1, IUK2 and IUK3 can also be seen: Due to the extremely delicate design of the spokes 7 according to the invention, the permanent magnets 5 can be arranged very close to each other, so that the permanent magnets 5 in the area of ​​IUK3 have a proportion of more than 50% (cf. e.g. also the embodiment according to Fig. 2) and occupy more than 82% of the respective circumferential length of the inner circumferential circle in the areas of IUK1 and IUK2. This design thus enables, in particular, a high number of poles PZ. R of the rotor 3.

[0082] In the xy-plane of the Fig. Figure 1 also illustrates a radial direction R, where it can be seen that the permanent magnets 5 extend predominantly in this direction R because they are longer in the radial direction than they are wide perpendicular to this direction R.

[0083] In the circumferential direction between the permanent magnets 5, the rotor 3 forms spokes 7, which are aligned along the radial direction R. These spokes 7 at least partially delimit the magnet pockets 8: While the magnet pockets 8 extend from the inner circumferential circle IUK1 to the inner circumferential circle IUK3, the spokes 7 run from the illustrated further inner circumferential circle IUK2 to the outer circumference of the rotor 3 (which has a diameter of D). R = 2R R exhibits). In the example of the Fig. Although permanent magnets 5 are inserted into the magnet pockets 8, these permanent magnets 5 only partially fill the magnet pockets 8 because the cuboid permanent magnets 5 extend radially inwards only as far as circle IUK2, from which point the magnet pockets 8 taper radially inwards. All of the permanent magnets 5 of the rotor 3 shown are designed to be free of rare earth elements.

[0084] In the example of the Fig. 2 and Fig. 3 as in the example of the Fig. 4, Fig. 5 to Fig. 6 as well as in the further example of the Fig. 7. The permanent magnets 5 shown there completely fill the respective magnet pockets 8 (except for certain necessary mounting gaps), so that the permanent magnets 5 extend to the inner circumferential circle IUK1 and thus: RLM = RLMT. In Fig. 2 and Fig. Figure 3 also shows that the circumferential width M of the permanent magnets 5 is larger than the circumferential width S of the respective spoke 7 (measured at the height of the inner circumferential circle IUK3). Fig. Figure 2 also indicates where exactly a screw connection 29 of the package of rotor sheets 33 forming the rotor 3 can be sensibly placed on each spoke 7 and, based on the dashed circumferential line, how far a finishing plate 30 as previously described, which bridges adjacent spoke heads 25, could extend.

[0085] In all examples, the respective spokes 7 extend only as far as the inner circumferential circle IUK2. The connection between each spoke 7 and the central area 11 of the rotor 3 is established via connecting webs 15, which thus extend from IUK1 to IUK2. These connecting webs 15 also define the respective magnet pocket 8. In all examples, the permanent magnets 5 are designed as ferrite magnets.

[0086] Especially in Fig. Figure 1 clearly shows that the minimum circumference b of these connecting webs 15 is chosen to be very narrow; it can be less than 1.90 mm.

[0087] Characteristic of designs according to the invention (as in Fig. (1 shown) are the particularly delicately designed spokes 7: If one considers, for example, the angular range α, which the respective spoke 7 (relative to the center M of the rotor 3 and at the height of the radially outermost inner circumcircle IUK3, to which the permanent magnets 5 extend), neglecting the projections 31 shown, one can see that in the example of the Fig. 1 the angle α is less than 8°.

[0088] In Fig. Figure 1 clearly shows that each of the spokes 7 forms two longitudinal edges 18 against which the permanent magnets 5 lie flat. These longitudinal edges 18 run obliquely to the radial direction R and extend radially outwards from the inner circumferential circle IUK2 to the circle IUK3, defining an angle β.

[0089] In the simulation example of the Fig. 1 The rotor there carries a total of 30 magnets 5, from which a pole number P ZR = 30 results, while stator 2 has a total of 30 slots. The one in Fig. The rotor 3 shown, however, has a total of 24 magnets 5 and thus forms a number of P ZR = 24 magnetic poles on its outer circumference.

[0090] In Fig. 1. Furthermore, the ratio of the maximum outer diameter D can also be calculated. R = 2R R of rotor 3 and the maximum outer diameter D Sof the stator 2; this ratio can be read in the case of drive motors 1 according to the invention at D R / D S > 0.72.

[0091] If you are in Fig. If we consider the radially outermost point of each permanent magnet 5 (which abuts the circle IUK3) and determine the circumferential length of each magnet 5 in this region as the magnet width M, we find that this magnet width M is greater than the spoke width S measured at the same radial height and in the same manner. In other words, at the radially outermost point, the permanent magnets 5 have a greater length along the circumference than the spokes 7 located between them. Such a design is made possible by the particularly narrow design of the spokes, as can be seen in particular from the angle β in Fig. 1 recognizes: This angular range β is the one occupied by the spoke 7 in the area of ​​its longitudinal edges 18 and in the example of the Fig. 1 less than 14°.

[0092] In all embodiments shown in the figures, the respective permanent magnets 5, with respect to the xy-radial plane, exhibit a cross-section described by a polygon. In the case of the Fig. 1. All permanent magnets 5 are cuboid in shape. In the case of the Fig. 2 and Fig. In contrast, the permanent magnets 5 there each show a radially internal wedge-shaped area 20, which has a trapezoidal shape and thus optimally fills the area of ​​the respective magnet pocket 8 which is limited by the two connecting webs 15.

[0093] In the case of the Fig. 4, Fig. 5 to Fig. In contrast, two different geometry types A and B of permanent magnets 5 are used, with type A also being as in the example of the Fig. Type 3 has a trapezoidal area 21, whereas type B is cuboid and therefore easier to manufacture. Nevertheless, even in the example of the Fig. 4, Fig. 5 to Fig. 6. The respective magnetic pocket 8 is completely filled by the respective permanent magnet A or B, with the magnetic pockets 8 having different shapes. In order to enable complete filling of the magnetic pockets 8 despite the cuboid shape of the magnets of type B, the following applies in the example of Fig. 4, Fig. 5 to Fig. 6 the connecting webs 15, more precisely their mean direction 23, are oriented obliquely to the radial direction R. In Fig. 4 can be seen that the directions 23 of adjacent connecting webs 15 intersect in the central area 11 of the rotor 3.

[0094] The example of Fig. Figure 7 shows that a drive motor 1 according to the invention with fully filled magnetic pockets 8 can also be realized without any wedge shape of the permanent magnets 5, namely by having the magnetic pockets 8 comprise two rectangular areas 19a and 19b of different sizes, which follow one another in the radial direction R. The radially outer rectangular area 19b of the magnetic pockets 8 is bounded by the longitudinal edges 18 of the spokes 7, while the radially inner rectangular area 19a is bounded by the connecting webs 15, which connect the spokes 7 to the central area 11. The connecting webs 15 therefore each have a trapezoidal cross-section in the xy-plane in this example. The two types of cuboid-shaped permanent magnets A and B are shown in the example of Fig. The magnets are arranged one behind the other in the radial direction R and touch each other with their end faces. The magnets of type B extend over the radial length RLS of the connecting webs 15 from IUK1 to IUK2; the magnets 5 of type A, on the other hand, extend from IUK2 to IUK3.

[0095] In the design example of the Fig. 8 are as already in the example of the Fig. 7. The two magnetic pockets 19a and 19b are connected to each other (they merge into one another), and two different geometric types A and B of permanent magnets 5a and 5b are again inserted into the resulting common magnetic pocket, with the two different magnets 5a and 5b again arranged one behind the other in the radial direction R and following each other directly (in the radial direction R) and thus being in direct contact with each other (in the radial direction R). In contrast to Fig. Type B has 7 in Fig. 8 now, however, a wedge shape is formed (radially on the inside) (note the thin dashed guidelines that extend to the rotor center). Here, the outer edges 32 of the radially arranged permanent magnets 5a of type B are clearly oriented along the radial direction R. This has the particular advantage that the connecting webs 15 (which extend between IUK1 and IUK2 and connect the central area 11 with the middle area 12 of the rotor 3) have a constant width in the circumferential direction.

[0096] With respect to the xy-radial plane, the permanent magnets 5a show in Fig. 8 has a trapezoidal cross-section; the cross-section of magnets 5b, however, is rectangular. The permanent magnets 5b thus have a rectangular / cuboid shape that is easy to manufacture, analogous to type A in Fig. 7. As with all embodiments shown in the figures, the individual (each designed in one piece) rotor laminations 33 each form the entire cross-section of the rotor 3 in the xy-radial plane (in which the radial direction R lies).

[0097] In summary, an optimized spoke design for a rotor 3 of an electric drive motor 1 is proposed, enabling the use of ferrite-based permanent magnets 5. The rotor design is characterized by particularly delicate spokes 7, which allow for an increase in magnetic flux and thus the generation of high torques, especially when starting the motor 1, as required when using the drive motor 1 as a lifting motor in an elevator system (see Figure 1). Fig. 1). Reference symbol list 1 drive motor (can be used as a lifting motor in an elevator system) 2 Stator 3 Rotor 4 Stator winding 5 permanent magnets 6 Rotation axis 7 spokes 8 magnetic pockets (= holding pockets for 5) 9 grooves (out of 2) 10 Outer circumference (of 3) 11 central area (out of 3) 12 middle area (of 3; includes 15 in radial direction and part of 7) 13 outer area (of 3; includes part of 7) 14 Circumferential pole section (radially outer part of 3 / 7; forms 13) 15 Connecting bridge (connects 7 with 11 / 16) 16 Rotor yoke 17 Mounting hole (of 3 / 11, for mounting a motor shaft) 18 longitudinal edges (or longitudinal surfaces of 7) 19 rectangular area (out of 5) 20 wedge-shaped area (out of 5) 21 trapezoidal area 22 radial length (of 15) 23 Direction of travel (out of 15) 24 teeth (out of 2) 25 spoke head 26 Air gap (between 25; length in circumferential direction: g) 27 magnetic pole 28 Motor axle 29 (axial) screw connection 30 End plate (limits 5 in axial direction) 31 Holding projection (with radially inward circumferential length u) 32 Outer edge (of 5) 33 Rotor plate Geometry and design parameters of the drive motor N N Number of stator slots: 2 PZ R Number of rotor poles: 3 N PM Number of permanent magnets on the rotor: 5 PZ S Stator pole count: 2 R Radial direction α angular range relative to the center point M of the rotor 3, which is occupied by a spoke 7 (neglecting the retaining projections 31). β Angle range occupied by the respective spoke 7 in the area of ​​its longitudinal edges 18 γ angular range referred to the center point M of the rotor 3, which is occupied by a permanent magnet (5) at its radially outermost end in the radial plane δ is the angular range, relative to the center point M of the rotor 3, occupied by a spoke head 25 of a spoke 7 (taking into account the retaining projections 31); due to the retaining projections 31, δ > α b Width of the connecting webs 15 in the circumferential direction d Distance in radial direction between the outer circumference of the rotor 3 and the radially outer end of the respective permanent magnet 5 (corresponds to the radial height of the retaining projections 31 or the radial extent of the outer area 13 of the rotor 3) g Length in the circumferential direction of the air gaps that exist between individual spoke heads 25 of the rotor 3 Circumference length of one of the retaining projections 31 (measured on the radially inner side) D B"Bore diameter" = inner diameter of the stator 2 D R Outer diameter of the rotor 3 D S Stator outer diameter 2 LS radial length of the air gap between rotor and stator M Circumference width of a permanent magnet 5, measured along the circumference at its radially outer end RT radial depth (measured from the center M of the rotor 3) to which the magnet pockets 8 extend radially inwards RLM length over which the permanent magnets 5 extend in a radial direction RLMT Length over which the magnetic pockets 8 extend in a radial direction RLS length over which the connecting webs 15 extend in a radial direction S Circumference width of a spoke 7, measured along the circumference at its radially outer end IUK2 Inner circumferential circle to which the spokes 7 extend radially inwards IUK1 Inner circumferential circle to which the connecting webs 15, which connect the spokes 7 to the central area 11 of the rotor 3, extend from IUK2 IUK3 radial outermost inner circumferential circle to which the permanent magnets 7 extend

Claims

[1] Drive motor (1), - which is designed as a lifting motor for an elevator system, with - a stator (2) having a stator winding (4) for generating a rotating magnetic field, which is inserted into slots (9) of the stator (2), and - a rotor (3) rotatably mounted about a rotational axis (6), which carries a plurality of permanent magnets (5) and is designed as an internal rotor, - wherein the axis of rotation (6) defines a radial direction R in an xy-radial plane perpendicular to the axis of rotation, - wherein the permanent magnets (5) extend predominantly in the radial direction R and - wherein the rotor (3) forms spokes (7) extending along the radial direction R, which define magnet pockets (8) in the circumferential direction of the rotor (3), into which the permanent magnets (5) are inserted, characterized by , - that the permanent magnets (5) are designed as ferrite magnets. [2] Drive motor (1) according to claim 1, - wherein a respective magnet width M of the permanent magnets (5), each measured in the circumferential direction as a circumferential length at the radially outermost point of the respective permanent magnet (5), is greater than a respective spoke width S, which is also measured in the circumferential direction as a circumferential length at the height of the radially outermost point of the respective permanent magnet (5), such that: M > S. [3] Drive motor according to claim 1 or claim 2, wherein the rotor (3) forms three radial areas, namely - a central area (11) which forms a receiving hole (17) for receiving a motor shaft of the drive motor (1), - a central region (12) in which the permanent magnets (5) extend in a radial direction, wherein the central region (12) is formed by the spokes (7) and by connecting webs (15), and the connecting webs (15) each connect one of the spokes (7) to the central region (11), and a - outer area (13), which is radially outside and forms a circumferential outer contour of the rotor (3), - in particular wherein the rotor (3) is constructed from a package of metal sheets which follow one another in an axial direction and each run parallel to the xy-radial plane, and wherein these metal sheets each form the entire rotor cross-section, i.e. the central area (11), the middle area (12) and the outer area (13). [4] Drive motor (1) according to any one of the preceding claims, - wherein the magnetic pockets (8) extend to a radial depth RT, which is measured from the center M of the rotor (3) and for which, compared to the radius R R of the rotor (3) the following applies: 0.45 R R < RT < 0.55 R R . [5] Drive motor (1) according to any one of the preceding claims, - wherein the ferrite magnets (5) are designed to be free of rare earth elements or - wherein the ferrite magnets (5) each contain a total rare earth content of less than 15 wt%, preferably less than 10 wt%. [6] Drive motor (1) according to one of the preceding claims, - wherein an angular region γ occupied by the respective permanent magnet (5) at its radial outermost end in the radial plane is larger than an angular region α occupied by an adjacent spoke (7) in the radial plane at the same radial height, each with reference to the center of the rotor (3), such that: γ > α. [7] Drive motor (1) according to one of the preceding claims, - where for a ratio between a maximum outer diameter D R of the rotor (3) and a maximum outer diameter D S of the stator (2) holds: D R / D S > 0.70, - preferably applies: D R / D S > 0.

75. [8] Drive motor (1) according to any one of the preceding claims, - wherein the spokes (7) in a radial region in which the permanent magnets (5) are arranged, each with respect to a center point M of the rotor (3), occupy an angular range α and wherein: α<18°, - preferably: α < 15°, - particularly preferred is: α < 10° or even α < 8° or where: α < 0.0125° × PZ R 2 - 0.925° × PZ R +22.5°, with PZ R the number of poles of the rotor (3). [9] Drive motor (1) according to any of the preceding claims, - wherein each of the spokes (7) forms two straight longitudinal edges (18) as contact surfaces for the permanent magnets (5), preferably wherein the longitudinal edges (18) extend along a respective radially outer region (19) of the respective permanent magnet (5) in the radial plane and / or - wherein the spokes (7) extend to an inner circumferential circle IUK2 with radius R IUK2 extend - in particular wherein the longitudinal edges (18) lead radially outwards from the inner circumcircle IUK2, - wherein connecting webs (15) connecting the spokes (7) to a central area (11) of the rotor (3) extend radially on the inside to an inner circumferential circle IUK1 with radius R IUK1 extend and - where for a length RLS = R IUK2 -R IUK1 The radial extent RLM of the connecting webs (15) of the permanent magnets (5) is: RLS < 0.16 RLM, preferably: RLS < 0.14 RLM or even RLS < 0.12 RLM. [10] Drive motor (1) according to one of the preceding claims, wherein for a number N PM of the permanent magnets (5) applies: N PM ≥ 20, preferably: N PM ≥ 24 or even N PM ≥ 28 and / or - where PZ applies R ≤ 40, PZ R ≤ 36 or even PZ R ≤ 32, with PZ R = N PMthe number of poles of the rotor (3), and / or - where for a number N N at slots (9) of the stator (2) the following applies: N N ≥ 24, preferably: N N ≥ 28 or even N N ≥ 32 and / or - where for the number N N at slots (9) of the stator (2) the following applies: N N ≤ 72, preferably: N N ≤ 54. [11] Drive motor (1) according to any one of the preceding claims, - wherein the ferrite magnets (5) are designed with a magnetic flux density of at least 0.35 T and / or - wherein each radially outer end of the respective permanent magnet (5) is spaced apart in the radial direction R by a distance d from an outer circumference (10) of the rotor (3). [12] Drive motor (1) according to any one of the preceding claims, - wherein the permanent magnets (5) each extend in the radial direction R over a radial length RLM, for which in relation to the radius R R of the rotor (3) applies: RLM ≥ 41% R R , preferably: RLM ≥ 42% R R ; and / or RLM ≤ 49% R R , preferably: RLM ≤ 48% R R. [13] Drive motor (1) according to any of the preceding claims, - wherein the spokes (7) are connected via connecting webs (15) to a central area (11) of the rotor (3), which is preferably designed to be free of air pockets, - preferably wherein the permanent magnets (5) extend to an inner circumferential circle IUK1, at which the connecting webs (15) transition into the central area (11) of the rotor (3) and / or - preferably wherein the connecting webs (15) have a circumferential width b of b < 1.80 mm at their thinnest points in the circumferential direction. [14] Drive motor (1) according to any one of the preceding claims, - wherein all of the permanent magnets (5) carried by the rotor (3) have a polygonal cross-section, at least partially or completely, with respect to the radial plane, - preferably wherein at least some or all of the permanent magnets (5) carried by the rotor (3) have a radially inward wedge-shaped region (20), in particular a trapezoidal region (21), and / or - wherein all of the permanent magnets (5) carried by the rotor (3) have at least one rectangular area (19) in the radial plane. [15] Drive motor (1) according to any one of the preceding claims, - wherein the permanent magnets (5) comprise two different geometry types A and B and / or the magnetic pockets (8) have different shapes, - preferably wherein the two different geometry types A and B of the permanent magnets (5) - are inserted alternately in the circumferential direction into the magnetic pockets (8) or - are arranged one behind the other in a radial direction R, - particularly preferred, wherein, in each case with reference to the radial plane, - the permanent magnets (5) of geometry type A have a rectangular cross-sectional shape and / or - the permanent magnets (5) of geometry type B have a wedge shape on the radial inside, in particular a trapezoidal area. [16] Drive motor (1) according to any one of the preceding claims, - wherein the spokes (7) of the rotor (3) are connected to the central area (11) of the rotor (3) via connecting webs (15) and wherein a respective mean direction (23) of one or all of these connecting webs (15) is oriented obliquely to the radial direction R, in particular at an angle of > 5° to the radial direction R, in particular wherein the directions (23) of adjacent connecting webs (15) intersect, preferably in the central area (11) of the rotor (3). [17] Drive motor (1) according to any of the preceding claims, - wherein one or all of the magnetic pockets (8), with respect to the radial plane, show a cross-section comprising two rectangular areas (19a, 19b) of different sizes, - in particular wherein a radially outer of the two rectangular areas (19b) abuts longitudinal edges (18) of the spokes (7), while a radially inner of the two rectangular areas (19a) abuts connecting webs (15) of the rotor (3) which connect the spokes (7) to a central area (11) of the rotor (3), and / or - wherein two different geometry types A and B of the permanent magnets (5), - in particular two different cuboid permanent magnets (5a, 5b), are arranged one after the other in the radial direction R in the respective magnetic pocket (8a, 8b), - preferably wherein a type B permanent magnet (5a) which is arranged radially inside the rotor (3) has a wedge shape on its radial inside side, particularly preferably wherein outer edges (32) of this type B extend along the radial direction R. [18] Drive motor (1) according to any of the preceding claims, - wherein at the radial height of a radially outermost inner circumcircle IUK3, to which the permanent magnets (5) extend, the permanent magnets (5) occupy a total of at least 50%, preferably at least 51%, of a circumferential length of IUK3 and / or - wherein at the radial height of an inner circumferential circle IUK1, at which connecting webs (15) connecting the spokes (7) to the central area (11) of the rotor (3) transition into the central area (11), the permanent magnets (5) cover a total of at least 84%, preferably at least 86% of a circumferential length of IUK1 and / or - wherein, at the radial height of an inner circumferential circle IUK2, at which the connecting webs (15) transition into the spokes (7), the permanent magnets (5) cover a total of at least 85%, preferably at least 87%, of a circumferential length of IUK2. [19] Drive motor (1) according to one of the preceding claims, wherein individual, but preferably all, of the permanent magnets (5) carried by the rotor (3) project in the axial direction of the axis of rotation (6) beyond the stator (2) and / or beyond the rotor (3), - preferably wherein this axial projection is designed on both sides and is at least 5 mm on both sides of the stator (2), - in particular wherein the rotor (3) does not protrude beyond the stator (2) or protrudes beyond it by at most 10% of an axial length of the stator (2) on both sides. [20] Drive motor (1) according to any one of the preceding claims, - where for a rotor outer diameter D R of the rotor (3) the following applies: D R = [130 - 180] mm and / or - where for the number of poles PZ R of the rotor (3) applies: 8 ≤ PZ R ≤ 14, preferably wherein furthermore for the number N N at slots (9) of the stator (2) 9 ≤ NN ≤ 15, or PZ R ≤ 36, preferably wherein N further applies N ≤ 48, or PZ R ≤ 32, preferably wherein N further applies N ≤ 40.

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