Laminations of a laminated core and rotor of a rotating electrical machine having a plurality of laminations

Abstract

The invention relates to a lamination for a laminated core and a rotor for a rotating electrical machine having a plurality of such laminations. A lamination (1) for a laminated core of a rotor for a rotating electrical machine, the lamination having a substantially annular shape, characterised in that the lamination (1) comprises: a plurality of first sectors (10) having a higher radial compressive strength at least on the radially inner side (3); and a plurality of second sectors (30) having a lower radial compressive strength at least on the radially inner side (3). By means of the lamination proposed here, an element carrying the magnets of the rotor of the rotating electrical machine is presented which has a minimal tendency to generate imbalances and can be mounted in a simplified manner.

Description

Technical Field

[0001] The invention relates to laminations of a laminated core and to a rotor of a rotating electrical machine having a plurality of such laminations. Background Art

[0002] Rotors of permanently excited synchronous machines are known from the prior art, which have magnets on their radial outer sides, which are arranged in pocket-like recesses in the rotor or in a lamination stack consisting of laminations.

[0003] The radially inner regions of these laminations are arranged on the respective rotor shafts. To transfer torque from the shaft to the laminations or vice versa, torque transmission means acting in a form-fitting manner are usually used, such as lugs on the laminations that engage in grooves on the shaft.

[0004] To facilitate assembly of the laminations, the laminations are typically seated on the shaft with a clearance fit.

[0005] In the central radial region of the lamination, the lamination can have recesses to reduce the mass or mass moment of inertia. These recesses are evenly distributed over the circumference.

[0006] Due to the large mass of the magnets arranged radially outward, imbalances can occur in the rotor, particularly during dynamic events such as speed shocks, speed changes, engagement of the parking lock, etc. This imbalance corresponds to play or displacement of the lamination stack. Even devices for axial biasing, such as a central screw in the shaft, cannot always reliably compensate for this displacement or imbalance.

[0007] The resulting imbalance can exceed the forces permitted by standards or the usual requirements of the vehicle manufacturer. In addition to the signs of wear associated with imbalance, disruptive noise emissions are also frequently noted.

[0008] At high rotor speeds, severe deformations can occur in the radially inner regions of the laminations. These radial deformations must be taken into account when designing the inner diameter of the laminations. This often results in a strong overlap with the shaft diameter and, therefore, the aforementioned interference fit over almost the entire circumference of the shaft-mounting portion of the laminations. However, this interference fit results in significantly higher friction forces that must be overcome during assembly, or significantly higher wear and / or energy consumption when performing assembly, such as during warm-up. Summary of the Invention

[0009] Proceeding from this, the object of the present invention is to provide a lamination of a laminated core of a rotor of a rotating electrical machine and the rotor itself, wherein the laminations in the laminated core have a low tendency to develop imbalances and can be assembled in a simplified manner.

[0010] Features of the claims may be combined in any technically useful way, including features of the description in the following description and drawings comprising additional embodiments of the invention.

[0011] The present invention relates to a lamination of a laminated core of a rotor for a rotating electrical machine, the lamination having a substantially toroidal shape, wherein the lamination comprises a plurality of first sectors having a higher radial compressive strength at least on the radially inner side and a plurality of second sectors having a lower radial compressive strength at least on the radially inner side. The lamination is therefore a so-called stacked lamination of the rotor for the rotating electrical machine.

[0012] In the context of the present invention, the terms “radial direction” and “circumferential direction” always refer to the axis of rotation of the lamination stack or of a rotor equipped with the lamination stack.

[0013] Because the rotor or laminations are designed as a hollow cylinder or ring, each sector is a ring sector, with the centers of the first and second sectors located at the center of the ring. Consequently, each sector has the shape of an angular surface with a clear center. In this case, the shape of the laminations can deviate slightly from the ring shape both radially inside and radially outside the ring.

[0014] According to the invention, the compressive strength of the first sector on the radially inner side of the first sector is greater than the compressive strength of the second sector on the radially inner side of the second sector.

[0015] The compressive strength that is relevant here is the strength of the respective “sector” on the radial inside under radial pressure relative to its yield point, ie relative to its elastic deformability.

[0016] In particular, it can be provided that the lamination has an equal number of first sectors and second sectors.The first sectors and second sectors should be arranged alternately in the circumferential direction.

[0017] The first sector, which has a greater radial compressive strength, ensures that there is essentially no radial displacement relative to the rotor axis and, therefore, no imbalances occur, even in the event of high loads on the laminations during operation of the rotor. Due to the fact that the radial inner side of the lamination is not formed entirely by the first sector, but by the first and second sectors, and therefore by sectors of higher and lower radial strength, the laminations, and accordingly the assembly of a laminated core having several such laminations on a shaft, can be performed with less installation effort or with lower forces and / or with lower heat input.

[0018] In an advantageous embodiment, radially inwardly directed projections can be arranged in the first sector on its radial inner side for contacting the outer side of the shaft. This means that the laminations have their smallest radial width in the region of greatest radial compressive strength, which is delimited in the inner region by the corresponding projections. Such projections can also be referred to as centering cams.

[0019] An alternative embodiment provides that the radial inner side of the annular core is essentially delimited in the shape of a polygon, wherein the polygon has rounded corners and / or convex edges.

[0020] In particular, the respective corner regions of the polygon can be located in the respective first sectors. This means that the radial inner side of the lamination or its annular shape is designed to be most pressure-resistant in the radial direction where the corners or corner regions of the polygon of the cross-sectional area of ​​the central opening of the annular ring are located.

[0021] In an advantageous embodiment, the polygon can essentially have a triangular shape. In particular, the polygon can be designed in the form of an equilateral triangle. The triangle can be rounded at its corners and sides, thereby forming an equilateral triangle with rounded corners or a basil triangle with rounded corners.

[0022] In the case of a polygonal shape designed as a rounded equilateral triangle or a rounded basil triangle, there are only three first sectors in which the corner regions of the triangle are arranged. These three first sectors are arranged alternately on the circumference with three second sectors in which the central regions of the three sides of the triangle are arranged in sequence.

[0023] By means of the relief pattern thus achieved, the required overlap of the polygonal profile with the shaft is significantly reduced. Advantages are lower assembly forces or lower joining temperatures or higher permissible speeds compared to rotor laminations without such a relief pattern.

[0024] For optimal pressure distribution, a first window is arranged in the first sector, located between a first radius and a second radius greater than the first radius. This first window is also referred to as the radially inner window. The first window is preferably elongated and axisymmetric, with rounded corners. The side of the first window facing the center of the annular shape of the lamination stack can lie on an arc of a circle having the first radius.

[0025] The side of the first window facing away from the center of the circular ring shape of the sheet can be located essentially on the following arc, at least in the central area, the center of the arc corresponds to the intersection of the radial inner edge of the ring and the straight line extending radially from the center of the circular ring shape, and the first window is mirrored on this straight line.

[0026] Two elongated windows may be arranged in the second sector, the two elongated windows being arranged between the third radius and a fourth radius larger than the third radius, and the two elongated windows being arranged axially symmetrically with respect to a bisector of the second sector.

[0027] The laminations can also be designed such that the respective elongated window extends in the region from the second sector to the first sector.In an advantageous embodiment, the third radius is greater than the second radius.

[0028] Furthermore, the elongated windows can each have a substantially triangular shape with rounded corners, in which case the side facing the center of the annular shape of the laminate can also be located substantially on an arc of a circle having a third radius. The triangular shape can optionally be designed as an isosceles triangle, wherein the longest side of the triangle is the side facing the center of the annular shape.

[0029] Furthermore, an outer window may be arranged in the second sector on a bisector of the second sector, the outer window being located between the fifth radius and a sixth radius that is larger than the fifth radius. In particular, the fifth radius may be smaller than the fourth radius.

[0030] The bisector of the second sector may be a mirror axis of the axisymmetric design of the outer window.

[0031] On the side of the outer window facing away from the center of the circular ring shape of the lamination stack, the outer window can be located, at least in the central region, on a circular arc having a radius substantially corresponding to the sixth radius. Starting from this circular arc, the outer window can be defined on the side of the outer window facing the center of the circular ring shape by limiting straight lines extending symmetrically with respect to the bisector and intersecting on the bisector.

[0032] A respective window is understood to mean a recess or a through-opening in the lamination stack.

[0033] In particular, it can be provided that the outer window is arranged equidistant from the two elongated windows, wherein linear elements of the laminate are formed between the outer window of the respective second sector and the two elongated windows, said linear elements also being referred to as torque struts. These linear elements can extend at an angle of 65° to 75°, in particular 69° to 72°, relative to the bisecting line of the second sector.

[0034] In a further advantageous embodiment of the core lamination, it can be provided that the angle of the second sector is 1.5 to 2.5 times greater than the angle of the first sector.

[0035] In particular, the angle of the first sector may be 30° and the angle of the second sector may be 60°, wherein the lamination stack comprises a total of four first sectors and four second sectors.

[0036] In an alternative embodiment, the angle of the first sector is 30° and the angle of the second sector is 90°, wherein the lamination comprises a total of 3 first sectors and 3 second sectors.

[0037] In the second sector, there is a torque transmission feature in the form of at least one tooth or lug, which can engage with a correspondingly formed complementary feature of the shaft for transmitting torque from the rotor to the shaft, or vice versa. On the outside of the laminations, this advantageously has pockets for receiving magnets, so that corresponding magnets can be housed on the radial outside of the laminated core formed by the plurality of laminations.

[0038] In particular, a toothing or nose is arranged in the second sector at a radially inner delimiting area of ​​the second sector. In the case where such a toothing or lug extends substantially radially, the radial expansion in the second sector is irrelevant to ensuring torque transmission.

[0039] The windows mentioned above form a repeating pattern in the laminations in the circumferential direction. This repeating pattern or relief pattern makes it possible to transmit very high torques with small shaft diameters and short axial lengths without play, even at very high speeds.

[0040] Another aspect of the invention is a rotor for a rotating electrical machine having a plurality of laminations according to the invention, which are arranged in a stacked manner to form a laminated core and are arranged coaxially with respect to the axis of rotation of a shaft of the rotating electrical machine.

[0041] The radially inner edge of the second sector may form an interference fit or a clearance fit with the shaft.

[0042] Preferably, there is an interference fit between the respective first sectors and the shaft so that no imbalance occurs during operation of the rotor. This interference fit should be within the following tolerance range: H7 / r6 to H7 / x8. For a nominal shaft diameter of 55 mm, the overlap between the shaft and the radially inner limit of the laminations can be 50 μm to 150 μm.

[0043] In an embodiment of the laminations in which a radially inwardly directed projection is arranged in the first sector on the radial inside of the first sector, the radial inside of the projection forms an interference fit with the shaft.

[0044] In embodiments where the radially inner side of the annular lamination is substantially defined by a polygonal shape, the corner regions of the polygon form an interference fit with the shaft. In alternative embodiments, the interference fit is achieved through the entire polygonal shape.

[0045] In this embodiment, it can also be provided that the cross-sectional area of ​​the shaft on which the lamination in question or the correspondingly shaped laminated core sits also has a polygonal shape, which corresponds in its dimensions to the proportions of the polygonal shape of the central area of ​​the lamination.

[0046] In particular, the number of second sectors may correspond to the number of pole pairs of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] The invention described above will now be described in detail based on the important technical background with reference to the relevant drawings, which show preferred embodiments. The invention is not limited in any way to the purely schematic drawings, wherein it should be noted that the exemplary embodiments shown in the drawings are not limited to the dimensions shown. In the drawings:

[0048] Figure 1 A lamination according to a first embodiment of the invention is shown in front view,

[0049] Figure 2 : Shown in side view Figure 1 The laminate shown,

[0050] Figure 3 : shows a laminate according to a second embodiment of the invention in elevation, and

[0051] Figure 4 : Shown in side view Figure 3 The laminations shown. DETAILED DESCRIPTION

[0052] Can be obtained from Figure 2 and Figure 4 As can be seen in FIG, the core lamination 1 is constructed essentially in two dimensions.

[0053] exist Figure 1 and Figure 3 In both embodiments of the laminated core 1 shown, the latter has recesses 2 on its radial outer side distributed around the circumference for accommodating the magnets. Figure 1 and Figure 3 The embodiment variants of the laminated plates 1 shown differ in the design of their respective radial inner sides 3. Figure 1 In the variant shown, the laminations 1 have radially inwardly oriented projections 50 on their radial inner sides 3. Furthermore, lugs 51 are arranged on the radial inner sides 3 offset by 180° and engage in grooves (not shown here) in the shaft of a rotor having the corresponding lamination 1 bundled with other laminations in a laminated core. The lugs 51 serve to transmit torque from the laminations 1 to the shaft or vice versa.

[0054] The projection 50 is adapted to bear against the radially outer side of the shaft in an interference fit.

[0055] The projections 14 , 50 are also referred to as centering cams.

[0056] exist Figure 3 In the embodiment shown, due to the shape of the polygon 60 forming the radial inner side 3 , the torque is transmitted in a form-fitting manner from the core stack 1 to the shaft or in the opposite direction.

[0057] The lamination stack 1 is divided into a plurality of first sectors 10 and a plurality of second sectors 30 , wherein the first sectors 10 and the second sectors 30 are arranged in an alternating manner on the circumference.

[0058] Figure 1 An embodiment with four first sectors 10 and four second sectors 30 is shown.

[0059] Figure 3 An embodiment is shown with three first sectors 10 and three second sectors 30 . The respective first sectors 10 and second sectors 30 are separated from one another by a transition region 20 .

[0060] A first window 13 is arranged in each first sector 10 and essentially has the shape of a segment of a circle. The side of the first window 13 facing the center of the laminate 1 lies on a first radius 11. The point of the first window 13 at the greatest radial distance from the center of the laminate 1 lies on a second radius 12. In the embodiment shown, the first window 13 is mirror-symmetrical with respect to a straight line 14, which represents the bisector of the first sector 10.

[0061] In the second sector 30, there are two elongated windows 33. Figure 1 In the embodiment shown, the elongated windows 33 overlap the transition region 20 , so that they protrude into the respective adjacent first sector 10 .

[0062] exist Figure 3 In the embodiment shown, the elongated windows 33 also protrude into the corresponding adjacent first sectors, but to a lesser extent. Figure 1 The embodiment shown.

[0063] The two elongated windows 33 are arranged in mirror symmetry with respect to the bisecting line 34 of the second sector 30. The radial innermost point of each elongated window 33 is located on the third radius 31. The radial outermost point of each elongated window 33 is located on the fourth radius 32. Figure 1 In the embodiment shown, the third radius 31 is smaller than the second radius 12 , but larger than the first radius 11 .

[0064] exist Figure 3In the embodiment shown, the fourth radius 32 is greater than the second radius 12. In the respective second sectors 30, outer windows 37 are arranged in a mirror-symmetrical manner with respect to the bisector 34 of the second sector 30. These outer windows are delimited on their side facing the center of the lamination stack 1 by two delimiting straight lines 38. The intersection of the two delimiting straight lines 38 lies on the respective bisector 34 of the second sector 30 in question and on the fifth radius 35. The radially outer side of each outer window 37 is defined by a respective arc 41, the radially outermost point of which lies on the sixth radius 36.

[0065] In both illustrated embodiments, the fifth radius 35 is smaller than the fourth radius 32 , but larger than the third radius 31 .

[0066] Between the respective outer windows 37 of the respective second sector 30 and the two elongated windows 33, corresponding torque struts 39 are formed, which extend at an angle 40 of approximately 70° relative to the bisector 34. The torque is transmitted from the magnet in the pocket 2 to the shaft or from the shaft to the magnet in the pocket by means of these torque struts 39.

[0067] exist Figure 3 In the embodiment shown, the radially inner region 3 is designed as a polygon 60 , wherein the polygon 60 essentially has the shape of an equilateral triangle with rounded corners 61 and convex edges 62 , so that overall a so-called Basil's triangle is formed.

[0068] The illustrated embodiments have in common that the lamination 1 has a relief pattern that repeats itself over the circumference, and that, due to the radially inner first windows 13 in the respective first sectors 10, the lamination 1 has a higher compressive strength on the radially inner side of the first sectors than on the radially inner side of the second sectors 30. This means that the lamination 1 can be drawn onto the shaft by means of the first sectors 10 in an interference fit, wherein the second sectors 30, which have a reduced compressive strength, can expand radially slightly and thus can be assembled more easily or with less production effort and / or energy consumption.

[0069] By means of the lamination proposed here, an element carrying the magnets of the rotor of a rotating electrical machine is presented which has a minimal tendency to generate imbalances and which can be mounted in a simplified manner.

[0070] Reference Signs List

[0071] 1 stacking

[0072] 2 concave holes

[0073] 3 Radially inner side

[0074] 10 First Sector

[0075] 11 First radius

[0076] 12 Second radius

[0077] 13 First Window

[0078] 14 straight line

[0079] 20 Transition Zone

[0080] 30 Second Sector

[0081] 31 Third Radius

[0082] 32 Fourth Radius

[0083] 33 Long Window

[0084] 34 Bisector

[0085] 35 Fifth Radius

[0086] 36 Sixth Radius

[0087] 37 External Window

[0088] 38 Delimitation Line

[0089] 39 Torque Strut

[0090] 40 degrees

[0091] 41 Arc

[0092] 50 protrusion

[0093] 51 lugs

[0094] 60 polygons

[0095] 61 Rounded corners

[0096] 62 convex edge

Claims

1. A lamination (1) of a laminated core of a rotor of a rotating electrical machine, said lamination having a substantially toroidal shape, characterized in that The laminate (1) has a plurality of first sectors (10) and a plurality of second sectors (30), wherein the first sectors have a higher radial compressive strength at least on the radial inner side (3), and the second sectors have a lower radial compressive strength at least on the radial inner side (3); the radial inner side (3) of the annular laminate (1) is substantially defined in the shape of a polygon, wherein the polygon (60) has rounded corners (61) and / or convex edges (62); the corresponding corner areas of the polygon (60) are located in the corresponding first sectors (10); a first window (13) is arranged in the first sector (10), and the first window is located between a first radius (11) and a second radius (12) that is larger than the first radius (11).

2. The laminate according to claim 1, wherein: The polygon (60) has substantially a triangular shape.

3. The laminate according to claim 1, wherein: Two elongated windows (33) are arranged in at least an area in the second sector (30), the two elongated windows are located between a third radius (31) and a fourth radius (32) greater than the third radius (31), and the two elongated windows are arranged axially symmetrically with respect to a bisector (34) of the second sector (30).

4. The laminate according to claim 3, wherein: An outer window (37) is arranged in the second sector (30) on the bisector (34) of the second sector (30), the outer window being located between a fifth radius (35) and a sixth radius (36) greater than the fifth radius (35).

5. A rotor for a rotating electrical machine comprising a plurality of laminations (1) according to any one of claims 1 to 4, the laminations being arranged in a stacked manner to form a laminated core and being arranged coaxially with the axis of rotation of a shaft of the rotating electrical machine.

6. The rotor of the rotating electrical machine according to claim 5, wherein: The radial inner edge of the second sector (30) forms a i) interference fit, or ii) clearance fit.

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