Electric motor rotor assembly

Abstract

The invention relates to an electric motor rotor assembly (2), having a central longitudinal axis (Z) which runs through the electric motor rotor assembly (2), at least two structural elements (4, 6, 8) which are arranged coaxial with respect to the central longitudinal axis (Z), also having at least one spring element (10, 12), which is arranged between the at least two structural elements (4, 6, 8) in a radial direction (R) and connects the corresponding structural elements (4, 6, 8) such that they are movable relative to each other.

Description

[0001] Electric motor rotor arrangement

[0002] The invention relates to an electric motor rotor arrangement according to the preamble of claim 1.

[0003] Electric motors consist of a stator and a rotor. The rotor, which is usually a single-piece rotating component, can be subject to noise, vibration, and driving oscillations. However, existing rotors exhibit inadequate NVH (noise, vibration, harshness) characteristics.

[0004] A first source of NVH can be the electric motor itself. Fluctuations in magnetic fields or torque pulses can add torque ripple (torsional vibration) to the rotating rotor. A second source of NVH can be the propagation of noise and vibration through a structure along a vibration path. Torsional vibration is transmitted through a gearbox, a differential, and a sideshaft or shaft, as well as the engine and / or transmission housing. The engine and / or transmission housing radiates airborne noise. Driveline vibrations can cause airborne noise at connected components along their length. To date, no satisfactory solution is known to effectively prevent or reduce rotor noise and vibration transmitted to the body or wheels.

[0005] The object of the invention is therefore to improve the state of the art accordingly.

[0006] Main features of the invention are defined in the characterizing part of claim 1. Embodiments are the subject of claims 2 to 9.

[0007] According to the invention, an electric motor rotor arrangement is proposed, comprising a central longitudinal axis which passes through the electric motor rotor arrangement, at least two structural elements which are arranged coaxially to the central longitudinal axis, wherein the electric motor rotor arrangement comprises at least one spring element which is arranged in a radial direction between the at least two structural elements and connects the corresponding structural elements in a relatively movable manner to one another.

[0008] The previously known, inherently rigid rotor is supplemented by torsional elasticity generated by the spring element. This creates an electric motor rotor assembly that is divided into two structural elements that can move relative to one another and can be considered or designed as masses. The structural elements can be rigid structural elements. Such vibration decoupling prevents noise and vibrations along a vibration path, along which vibrations are transmitted, from being transmitted via the rotor.

[0009] The structural elements can be separate components, such as the rotor shaft and the rotor base body. However, the first and second structural elements can also be sections of a single component, such as an inner radial rotor shaft section and an outer radial rotor shaft section. This demonstrates the variability of the invention. Due to the coaxial arrangement, the longitudinal axes of the structural elements and the central longitudinal axis coincide.

[0010] The structural elements can be arranged coaxially to the central longitudinal axis, with one of the two structural elements being arranged on the outer circumference of the other structural element. The spring element is arranged in the radial space between the two structural elements. The spring element can be an elastomer sleeve.

[0011] According to one conceivable embodiment of the electric motor rotor assembly, it can also comprise three structural elements, for example, a rotor shaft, a rotor base body, and a transmission input gear. It is conceivable that the three structural elements are arranged one behind the other with respect to a vibration path, preferably directly behind one another. Thus, for example, two of the structural elements can be connected to the third structural element via a spring element each.

[0012] According to one conceivable embodiment of the electric motor rotor assembly, the at least two structural elements are connected exclusively via a single spring element. This allows for vibration decoupling in a space-saving and effective manner.

[0013] According to a further embodiment of the electric motor rotor assembly, the spring element can be an elastomer spring, preferably formed from a magnetically active elastomer. Elastomer itself is inexpensive to produce and has sufficient spring properties, particularly in the area of ​​vibration decoupling. The elastomer removes material from the electric motor that could be affected by the magnetic field. Therefore, magnetically active elastomer can preferably be provided. The magnetically active elastomer has a higher magnetic permeability than the corresponding value of a pure elastomer material. This enables a spring element with significantly increased magnetic conductivity. Therefore, the magnetic field of the electric motor can act on the rotor in the best possible way, while simultaneously providing vibration decoupling.

[0014] A magnetically active elastomer can be a composite of an elastomer matrix and embedded magnetizable particles, particularly iron particles with high saturation magnetization. This also allows for further advantages when a magnetic field is applied. The particles can then be used to influence the spring stiffness, because reversible changes in the viscoelastic properties are related to the magnetic field strength, for example, an increase in the storage modulus G' and the loss modulus G". In other words, the spring element made of magnetically active elastomer can become stiffer with increasing field strength and softer with decreasing field strength.

[0015] According to a further embodiment of the electric motor rotor assembly, an inertial mass can be arranged on that structural element which is arranged on the side of the spring element facing the central longitudinal axis. The inertial mass can be a separate component and / or perform no further functions. The degree of vibration decoupling can thereby be increased in terms of frequency range and size, particularly in a configuration in which the inertial mass is arranged on a structural element which is mounted by means of bearings and thus "hangs freely." For example, a rotor shaft can hang freely. It is also conceivable for the inertial mass to be arranged along a vibration path between two spring elements on a structural element mounted by means of bearings. In particular, this can increase vibration decoupling.

[0016] According to a further embodiment of the electric motor rotor arrangement, the spring element can form a positive connection with at least one of the at least two structural elements. The positive connection can act in the circumferential direction. As a result, the spring element and the adjacent structural elements cannot critically rotate relative to one another about the central longitudinal axis, thus preventing spinning. This embodiment therefore enables continued operation in the event of a spring element failure. This positive connection can be achieved, for example, by means of a circumferential toothing contour or rib contour of the spring element running in the circumferential direction. It is also conceivable for both circumferential sides of the spring element to be contoured, so that a toothing or rib contour is formed in the circumferential direction. It is conceivable for the corresponding structural element to have a circumferential contour corresponding to the circumferential contour.Preferably, the two structural elements arranged on either side of the spring element overlap in the circumferential direction. This allows the spring element to be squeezed between the overlaps, thus preventing shearing and resulting damage to the spring element.

[0017] According to a further embodiment of the electric motor rotor assembly, the spring element can comprise at least one progression cavity. The progression cavity can extend longitudinally through the spring element entirely or only partially, with the progression cavity preferably being completely surrounded circumferentially by the material of the spring element to achieve the best possible progression. Because the progression cavity extends longitudinally, the progression acts circumferentially. The progression cavity leads to a progressive torsion characteristic (soft for normal operation / hard for torsional shocks) by closing radially on both sides of the spring element from a certain angle of rotation of the two structural elements.

[0018] According to a further embodiment of the electric motor rotor assembly, the spring element can comprise a separating element that separates the spring element into two radially adjacent spring element sections. This preferably increases the radial stiffness without, however, changing the torsional stiffness. This also makes it possible to achieve the lowest possible stiffness ratio of torsional stiffness to radial stiffness. The spring element sections can have identical radial thicknesses in the longitudinal and / or circumferential directions in order to achieve uniform stresses. The separating element can be a separating sleeve to which the two spring element sections are arranged in the radial direction, preferably bonded, more preferably vulcanized. The separating element can be made of a plastic, preferably a thermoplastic, or metal material.The advantage of the separating element is that it only has to separate the two spring element sections in the radial direction, which is why it can itself have a very small radial thickness, for example less than 1 mm.

[0019] According to a further embodiment of the electric motor rotor assembly, the spring element can have at least one rib projecting in the radial direction and extending in the longitudinal direction. Preferably, the spring element can have at least one outer rib projecting outward radially and extending in the longitudinal direction and / or at least one inner rib projecting inward radially and extending in the longitudinal direction. In addition, at least one of the at least two structural elements can have a rib curvature corresponding to the rib, outer rib, or inner rib, into which the at least one rib, outer rib, or inner rib projects, preferably an outer radial rib curvature and / or an inner radial rib curvature.

[0020] This also prevents the spring element and the at least one structural element comprising a rib curvature and adjacent to the spring element from critically rotating relative to one another about the central longitudinal axis, thus preventing spinning. This applies in particular to a spring element which does not have a material connection with the two radially adjacent structural elements. It is conceivable for the spring element to comprise a separating element, wherein the separating element forms the rib, outer rib or inner rib, for example by means of material thickening, so that the separating element has a greater radial material thickness in the region of the rib, outer rib or inner rib than in a region without a rib, outer rib or inner rib, or for example by means of a circumferential profile, so that the separating element has the same radial material thickness in the region of the rib, outer rib or inner rib and in a region without a rib, outer rib or inner rib.In the first case, a very rigid separating element can be formed, in which the rib, outer rib, or inner rib itself is / are hardly or only slightly flexible. In the second case, a cost-effective separating element can be formed, the circumferential contour of which can be produced, for example, by forming. It is conceivable that the separating element has a consistent radial material thickness in the circumferential direction. The spring element sections can have identical radial thicknesses in the longitudinal and / or circumferential directions to ensure uniform stress distribution.

[0021] In this case, a rib, outer rib, or inner rib, engages with the corresponding rib curvature. If the spring element also has a separating element, this design simultaneously serves to prevent rotation and increase radial rigidity without changing the torsional rigidity.

[0022] According to one conceivable embodiment of the electric motor rotor arrangement, the spring element can have an identical number of outer ribs and inner ribs, wherein the outer ribs and inner ribs can be arranged non-aligned in the radial direction. Adjacent outer ribs and inner ribs can therefore be offset from one another by an offset angle with respect to the central longitudinal axis in the range of 5° to 10°. This can achieve torsional progression of the vibration decoupling. For example, the non-aligned arrangement results in a reduction in the distance between two reference points on the structural elements when the two structural elements are rotated radially on both sides of the spring element about the central longitudinal axis, for example from a curved path or progression bevel on one of the structural elements to a curved path or progression bevel on the other of the structural elements.Any air gap that may exist circumferentially between an outer or inner rib and the corresponding structural element can close due to the twisting, and the spring element can then press against the corresponding structural element there as well. This achieves a torsional progression of the decoupling.

[0023] According to a further embodiment of the electric motor rotor arrangement, the at least one rib curvature can form a curved path and / or a progression slope, along which the rib, outer rib, or inner rib can slide during relative movement in the circumferential direction between one of the structural elements, which has the corresponding rib curvature, and the spring element, and is thereby subjected to radially inward or radially outward forces. This preferably also applies to a spring element that does not have a material connection with the two radially adjacent structural elements. A progressive behavior can also be achieved by means of the curved path and progression slope, particularly in the case where the spring element comprises a separating element.Due to the relative movement in the circumferential direction, the cam track and the progression bevel of the corresponding rib, outer rib, or inner rib define a direction of movement that includes radial components, whereby the spring element is then subjected to a force in the radial direction. An outer radial cam track or progression bevel results in a force being applied radially inward, while an inner radial cam track or progression bevel results in a force being applied radially outward.

[0024] According to one conceivable design of the electric motor rotor assembly, the cam track can have a profile that flattens toward a circumferential surface of the spring element. This allows the spring element to be subjected to increasing radial force as the angle of rotation increases, resulting in good progression. It is conceivable that the outer circumferential rib bulges each form a cam track that flattens in the opposite direction to the curve tracks formed by the inner circumferential rib bulges. The cam tracks thus have opposite courses in the circumferential direction. As a result, the direction of the relative movement in the circumferential direction is irrelevant, since the progressive behavior can be achieved in both directions.

[0025] According to a conceivable embodiment of the electric motor rotor arrangement, the progression slope can have a flat profile and / or be tilted relative to the radial direction or include a tilt angle with the radial direction. The progression behavior can be adjusted by means of the angle. It is conceivable that the rib curvature forms two progression slopes, namely one on each side of the rib, outer rib, or inner rib in the circumferential direction. Preferably, the tilt angles of the two progression slopes of a rib curvature are identical in order to achieve identical progression behavior regardless of the direction of the relative movement in the circumferential direction.

[0026] According to a further embodiment of the electric motor rotor arrangement, an air gap can be arranged in the circumferential direction between a rib, outer rib, or inner rib and the corresponding rib curvature. The air gap can exist over the entire radial overlap height between the rib, outer rib, or inner rib and the corresponding rib curvature. It is conceivable that an air gap is arranged in the circumferential direction on each side of the rib, outer rib, or inner rib. This allows the rib, outer rib, or inner rib to be spaced from the adjacent structural element on both sides in the circumferential direction in order to realize a torsional progression of the decoupling regardless of the direction of the relative movement in the circumferential direction. When the two structural elements are rotated radially on both sides of the spring element about the central longitudinal axis, the corresponding air gap closes first before the spring element rests against the structural element there.

[0027] According to a conceivable embodiment of the electric motor rotor assembly, at least one bearing can be provided, preferably a plain or rolling bearing, which supports at least one of the structural elements on a housing, in particular on an electric motor housing, and / or on a flywheel. The bearing, in particular the rolling bearing, can eliminate the radial and / or cardanic and / or axial degrees of freedom. For example, to meet strict gap and imbalance requirements, it may be advantageous to eliminate these degrees of freedom. However, the torsional degree of freedom, which influences vibration decoupling, is still present.

[0028] According to one conceivable design of the electric motor rotor assembly, the spring element or spring element sections can have a maximum radial thickness of 4 mm. The sum of the individual radial thicknesses of the two spring element sections can thus be a maximum of 4 mm. These dimensions represent an advantageous compromise between sufficient vibration decoupling and the lowest possible magnetic field influence.

[0029] According to a conceivable embodiment of the electric motor rotor assembly, one of the structural elements can be a rotor shaft, and the at least one spring element can be carried by the rotor shaft. The rotor shaft can be a solid shaft, a hollow shaft, or a hub. Due to a certain inertia of the rotor shaft, the arrangement of the spring element on the rotor shaft leads to advantageous vibration decoupling in the torsional direction above a certain frequency, thus reducing the high-frequency noise level.

[0030] According to a conceivable embodiment of the electric motor rotor arrangement, one of the structural elements can be a rotor base body, and the at least one spring element can rest against the rotor base body. The spring element can thereby decouple the rotor base body from vibrations of the other structural element, for example, the rotor shaft. The rotor base body can be designed as a laminated core and / or serve as a carrier for permanent magnets. The base body can be connected to the rotor shaft via the spring element. The base body can have a substantially cylindrical shape and extends along a rotational axis of the rotor shaft. When the spring element is arranged between the rotor base body and the rotor shaft, the spring element causes the rotor shaft to be a "freely suspended torsion element" and, due to its own inertia, serves to decouple vibrations in addition to its primary function, power transmission. This demonstrates the variability of the invention.

[0031] According to a conceivable embodiment of the electric motor rotor assembly, one of the structural elements can be a transmission input gear, and the at least one spring element can be in contact with the transmission input gear. This allows the spring element to decouple the transmission input gear from the other structural element, for example, the rotor shaft. When the spring element is arranged between the transmission input gear and the rotor shaft, the spring element causes the rotor shaft to be a "freely suspended torsion element" and, due to its own inertia, serves to decouple vibrations in addition to its primary function, power transmission. This also demonstrates the variability of the invention.

[0032] According to one conceivable embodiment of the electric motor rotor assembly, a first spring element can be arranged between the rotor base body and the rotor shaft, and a second spring element can be arranged between the transmission input gear and the rotor shaft. The provision of two such spring elements results in torsional elasticity at two locations with low torque (for example, on a primary side of the transmission) and a certain inertia between them, which is realized by the rotor shaft. This advantageously leads to pronounced torsional vibration decoupling above a certain frequency and thus reduces the high-frequency noise level.

[0033] According to a conceivable embodiment of the electric motor rotor assembly, the at least two structural elements can be first and second sections of a rotor shaft, first and second sections of a rotor base body, or first and second sections of a transmission input gear. This allows the spring element to be arranged within a single component, which is thereby divided into two parts.

[0034] According to a conceivable embodiment of the electric motor rotor assembly, the at least one spring element can either be connected in a materially bonded manner, preferably by vulcanization, to one or both radially adjacent structural elements, or can be arranged between the two radially adjacent structural elements without a material bond. A material bond enables a cost-effective and permanent connection. A materially bonded arrangement, in which the at least one spring element is held by means of a positive and / or non-positive connection, enables relative movement of the spring element to at least one adjacent structural element and, with appropriate design, also enables progressive behavior.

[0035] Further features, details, and advantages of the invention will become apparent from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. They show:

[0036] Fig. 1 is a longitudinal sectional view of an electric motor-gearbox unit with electric motor rotor arrangement;

[0037] Fig. 2 is a cross-sectional view of two structural elements with spring element;

[0038] Fig. 3 is a cross-sectional view of a spring element section;

[0039] Fig. 4 is a longitudinal sectional view of a spring element section;

[0040] Fig. 5 is a cross-sectional view of two structural element sections with spring element;

[0041] Fig. 6 is a cross-sectional view of two structural elements with a spring element of a further embodiment; Fig. 7 is a cross-sectional view of two structural elements with a spring element of a further embodiment and

[0042] Fig. 8 shows a diagram of the torsional vibration amplitude as a function of the excitation frequency.

[0043] In the figures, identical or corresponding elements are each designated by the same reference numerals and are therefore not described again unless expedient. Features already described are not described again to avoid repetition and are applicable to all elements with identical or corresponding reference numerals, unless explicitly excluded. The disclosures contained in the entire description are analogously transferable to identical parts with identical reference numerals or identical component designations. The positional information chosen in the description, such as top, bottom, side, etc., also relates to the directly described or illustrated figure and, in the event of a change in position, is to be transferred analogously to the new position.Furthermore, individual features or combinations of features from the different embodiments shown and described can represent independent, inventive or inventive solutions.

[0044] Figure 1 shows a longitudinal sectional view through an electric motor 31, which includes an electric motor housing 32. A gearbox 30, which includes a gearbox housing 34, is flanged to the electric motor 31. The electric motor 31 comprises a stator 24 and an electric motor rotor assembly 2, which is penetrated in the longitudinal direction L by a central longitudinal axis Z. A radial direction R and a circumferential direction U extend from this around the central longitudinal axis Z.

[0045] In the example shown, the electric motor rotor assembly 2 comprises three rigid structural elements 4, 6, 8, with the structural element 4 being a rotor shaft 4a. It is depicted here as a hollow shaft and is penetrated in the longitudinal direction L by a drive shaft 28, which can connect the transmission 30 to a gear (not shown). The rotor shaft 4a is mounted on the electric motor housing 32 and on a flywheel 48 via bearings 26.

[0046] Another structural element 6 is a rotor base body 6a. The rotor base body 6a is designed as a laminated core and / or serves as a carrier for permanent magnets. The structural elements 4, 6, or rotor shaft 4a and rotor base body 6a, are arranged coaxially to the central longitudinal axis Z, with the rotor base body 6a being arranged on the outer circumference of the rotor shaft 4a. In the radial direction R, a spring element 10 in the form of a sleeve-like elastomer spring 14 is arranged between the rotor shaft 4a and the rotor base body 6a. The spring element 10 is vulcanized there. The spring element 10 decouples the rotor shaft 4a and the rotor base body 6a from vibration, with the rotor shaft 4a and the rotor base body 6a being connected exclusively via the one spring element 10.

[0047] Another structural element 8 is a transmission input gear 8a. The transmission input gear 8a is the first gear of the transmission 30 facing the electric motor 31. The transmission input gear 8a is also arranged coaxially to the central longitudinal axis Z, with the transmission input gear 8a being arranged on the outer circumference of the rotor shaft 4a. In the radial direction R, a spring element 12 in the form of a sleeve-like elastomer spring 16 is arranged between the rotor shaft 4a and the transmission input gear 8a. The spring element 12 is vulcanized there. The spring element 12 decouples the rotor shaft 4a and the transmission input gear 8a from vibration, with the rotor shaft 4a and the transmission input gear 8a being connected exclusively via the one spring element 10.

[0048] The arrangement of the spring elements 10, 12, firstly between the rotor base body 6a and the rotor shaft 4a, and secondly between the transmission input gear 8a and the rotor shaft 4a, results in the rotor shaft 4a being a "freely suspended torsion element." It is also evident that the three structural elements 4, 6, 8 are arranged directly one behind the other along a vibration path.

[0049] The structural element 4 or the rotor shaft 4a carries an annular disk-shaped inertial mass 18. The inertial mass 18 is a separate component from the rotor shaft 4a and serves no function beyond that of an additional mass. It is also evident that the inertial mass 18 is arranged along the vibration path between the two spring elements 10, 12 on the structural element 4 or the rotor shaft 4a, which is supported by bearings 26.

[0050] Figure 2 shows a cross-sectional view of structural element 4 as rotor shaft 4a and structural element 6 as rotor base body 6a with a spring element 10 as an elastomer spring 14 arranged radially therebetween, preferably vulcanized thereon. Spring element 10 has a toothing pattern running in the circumferential direction U, which positively engages corresponding toothing contours of structural elements 4, 6. The outer circumferential toothing contour 10c of spring element 10 and the inner circumferential toothing contour 10d of spring element 10 result in a toothing pattern of spring element 10 in the circumferential direction. The two spring-element-side toothing contours 10c, 10d engage with corresponding toothing contours 4d, 6d in the adjacent structural elements 4, 6.It is also evident that the teeth of the toothing contour 4d of the structural element 4 also protrude somewhat into the toothing contour 6d of the structural element 6, resulting in an overlap in the circumferential direction U.

[0051] Figure 3 depicts a cross-sectional view of a section of a spring element 10 as an elastomer spring 14. The spring element 10 has a maximum radial thickness D of 4 mm. A cylindrical progression cavity 20 extends in the longitudinal direction L through the spring element 10, wherein the progression cavity 20 is completely surrounded circumferentially by the material of the spring element 10. Rotating the two adjacent structural elements (not shown in Figure 3) by a specific angle of rotation with respect to the central longitudinal axis Z results in a force F acting on the spring element 10, causing the progression cavity 20 to close or shrink.

[0052] Figure 4 shows a longitudinal sectional view of a section of a spring element 10 as an elastomer spring 14. The spring element 10 includes a separating element 22, which is designed as a separating sleeve. The separating element 22 is vulcanized into the spring element 10 and separates the spring element 10 into two spring element sections 10a, 10b of equal thickness. It is therefore also clear that the sum of the individual radial thicknesses of the two spring element sections 10a, 10b can thus be a maximum of 4 mm, thus corresponding to the radial thickness D.

[0053] Figure 5 shows a cross-sectional view of a different arrangement of a spring element 10, 12, the general nature of this figure being indicated by reference numerals. There, the spring element 10 or the spring element 12 is no longer arranged between two separate components, but rather within a single component, such as, for example, within the structural element 4 as the rotor shaft 4a, which is why it is divided into an outer-peripheral rotor shaft section 4b and an inner-peripheral rotor shaft section 4c. Likewise, the structural element 6 as the rotor base body 6a can be divided into an outer-peripheral rotor base body section 6b and an inner-peripheral rotor base body section 6c. This can also apply to the structural element 8 as the transmission input gear 8a, which is why it can be divided into an outer-peripheral transmission input gear section 8b and an inner-peripheral transmission input gear section 8c.

[0054] Figure 6 shows a cross-sectional view of the structural element 4 as rotor shaft 4a and the structural element 6 as rotor base body 6a with a spring element 10 as an elastomer spring 14 arranged radially therebetween, which spring element has a separating element 22 as a separating sleeve. The spring element 10 is free of any material connection with the adjacent structural elements 4, 6. The spring element 10 has a plurality of ribs 36, here exemplary twelve, projecting in the radial direction R and extending in the longitudinal direction L. More precisely, the spring element 10 comprises a plurality of outer ribs 36a projecting outwards radially and a plurality of inner ribs 36b projecting inwards radially, here exemplary six. The outer ribs 36a and inner ribs 36b are each arranged equidistant from one another in the circumferential direction U.The outer ribs 36a and inner ribs 36b are arranged non-aligned in the radial direction R and offset from one another by an offset angle W1 with respect to the central longitudinal axis.

[0055] The separating element 22 forms the ribs 36, or outer ribs 36a and inner ribs 36b, by having material thickening, so that the separating element 22 has a greater radial material thickness in the region B1 of the ribs 36, or outer ribs 36a and inner ribs 36b, than in a region B2 without ribs 36, or outer ribs 36a and inner ribs 36b. On the circumferential side, the separating element 22 is provided with the spring element sections 10a, 10b, which have identical radial thicknesses in the longitudinal direction L and in the circumferential direction U.

[0056] The structural element 6, as the rotor base body 6a, now has rib curvatures 38a corresponding to the outer ribs 36a. One of the outer ribs 36a projects into each of the rib curvatures 38a, with two air spacers 44 arranged in the circumferential direction U between one of the outer ribs 36a and the corresponding rib curvature 38a. Therefore, in the circumferential direction U, one air spacer 44 is arranged on each side of the outer ribs 36a.

[0057] The structural element 4, as the rotor shaft 4a, now also has rib curvatures 38b corresponding to the inner ribs 36b. One of the inner ribs 36b projects into each of the rib curvatures 38b, with two air spacers 44 arranged in the circumferential direction U between one of the inner ribs 36b and the corresponding rib curvature 38b. Therefore, an air spacer 44 is also arranged on each side of the inner ribs 36b in the circumferential direction U.

[0058] It can be seen that the rib indentations 38a, 38b each form a curved path 40a, 40b, along which the ribs 36, or outer ribs 36a and inner ribs 36b, can slide during relative movement in the circumferential direction U between the structural elements 4, 6. During relative movement, the outer radial curved paths 40a result in the spring element 10 being subjected to a force in the radial direction R inwards towards the central longitudinal axis Z, whereas the inner radial curved paths 40b result in the spring element 10 being subjected to a force in the radial direction R outwards away from the central longitudinal axis Z.

[0059] It is also evident that the rib indentations 38a, 38b each also form a progression bevel 42a, 42b, along which the ribs 36, or outer ribs 36a and inner ribs 36b, can slide during relative movement in the circumferential direction U between the structural elements 4, 6. During relative movement, the outer radial progression bevels 42a result in the spring element 10 being subjected to a force in the radial direction R inwards towards the central longitudinal axis Z, whereas the inner radial progression bevels 42b result in the spring element 10 being subjected to a force in the radial direction R outwards away from the central longitudinal axis Z, during relative movement. The progression bevels 42a, 42b each have a flat profile and are tilted relative to the radial direction R, which is why they enclose a tilt angle W2 with each other.

[0060] In this embodiment, a curved path 40a, 40b and a progressive slope 42a, 42b are located opposite each other with respect to the corresponding rib concavities 38a, 38b. Thus, in the circumferential direction U, a curved path 40a, 40b is arranged on one side of each rib 36, or outer rib 36a and inner rib 36b, and a progressive slope 42a, 42b is arranged on the other side.

[0061] The outer radial curved paths 40a each have a profile that flattens toward the outer circumferential surface of the spring element 10. The inner radial curved paths 40b each also have a profile that flattens toward the inner circumferential surface of the spring element 10. Advantageously, the outer radial curved paths 40a and the inner radial curved paths 40b flatten in opposite directions relative to the circumferential direction U, thereby realizing opposite courses of the curved paths 40a, 40b in the circumferential direction U.

[0062] Figure 7 shows a cross-sectional view of structural element 4 as rotor shaft 4a and structural element 6 as rotor base body 6a with spring element 10 arranged radially therebetween as elastomer spring 14, which has a separating element 22 as a separating sleeve. Since the electric motor rotor assembly 2 of Figure 7 is similar to that of Figure 6, only the differences from Figure 6 will be described to avoid repetition of Figure 7. Features not described shall be deemed to be disclosed and described.

[0063] The separating element 22 forms the ribs 36, or outer ribs 36a and inner ribs 36b, by means of a corresponding circumferential profile. The separating element 22 thus has the same radial material thickness in the region B1 of the ribs 36, or outer ribs 36a and inner ribs 36b, and in a region B2 without ribs 36, or outer ribs 36a and inner ribs 36b. The circumferential profile can be produced, for example, by forming the separating element 22.

[0064] The rib indentations 38a, 38b no longer have curved paths 40a, 40b. Instead, each rib indentation 38a, 38b has two progression slopes 42a, 42b, so that a progression slope 42a, 42b is formed on each side in the circumferential direction U of the corresponding rib 36, or outer rib 36a and inner rib 36b. The progression slopes 42a, 42b of a rib indentation 38a, 38b can have the same tilt angle W2; preferably, all tilt angles W2 of the progression slopes 42a, 42b of the rib indentations 38a, 38b are the same.

[0065] Figure 8 shows the effect of the electric motor rotor assembly 2 according to the invention compared to a known, rigid rotor. The diagram plots the amplitude of the torsional oscillation in radians (Y-axis) against the frequency in Hz (X-axis). A rotor known from the prior art was excited using an excitation frequency referred to as rotor excitation G1. A vibration response was recorded from a housing of the known rotor, referred to as the vibration response without spring element G2. The electric motor rotor assembly 2 according to the invention was also excited using this rotor excitation G1. A vibration response was recorded from a housing of the electric motor rotor assembly, referred to as the vibration response with spring element G3.

[0066] It is evident that the electric motor rotor arrangement 2 according to the invention leads to a lower, sometimes considerably lower, vibration response over the entire measured frequency, particularly in the higher frequency range.

[0067] The invention is not limited to one of the above-described embodiments, but can be modified in a variety of ways. All features and advantages apparent from the claims, the description, and the drawings, including structural details, spatial arrangements, and method steps, may be essential to the invention both individually and in a wide variety of combinations.

[0068] The scope of the invention includes all combinations of at least two of the features disclosed in the description, the claims and / or the figures.

[0069] To avoid repetition, features disclosed according to the device should also be considered as disclosed according to the method and be claimable. Likewise, features disclosed according to the method should be considered as disclosed according to the device and be claimable. Reference numeral l List of electric motor rotor arrangement B1 Area of ​​structural element B2 Area a Rotor shaft D Radial thickness b Rotor shaft section F Force c Rotor shaft section G1 Rotor excitation d Toothing contour G2 Vibration response without structural element spring element a Rotor base body G3 Vibration response with b Rotor base body section spring element c Rotor base body section L Longitudinal direction d Toothing contour R Radial direction of structural element U Circumferential direction a Gearbox input gear W1 Offset angle b Gearbox input gear section W2 Tilt angle c Gearbox input gear section Z Central longitudinal axis 0 Spring element 0a Spring element section 0b Spring element section 0c Toothing contour 0d Toothing contour 2 Spring element 4 Elastomer spring6 Elastomer spring 8 Inertial mass 0 Progression cavity 2 Separator 4 Stator 6 Bearing 8 Drive shaft 0 Gearbox 1 Electric motor 2 Electric motor housing 4 Gearbox housing 6 Rib 6a Outer rib 6b Inner rib 8a Rib concavity 8b Rib concavity 0a Cam track 0b Cam track 2a Progression slope 2b Progression slope 4 Air gap 8 Flywheel

Claims

Patent claims 1. Electric motor rotor arrangement (2), comprising a central longitudinal axis (Z) which passes through the electric motor rotor arrangement (2), at least two structural elements (4, 6, 8) which are arranged coaxially to the central longitudinal axis (Z), characterized by at least one spring element (10, 12) which is arranged in a radial direction (R) between the at least two structural elements (4, 6, 8) and connects the corresponding structural elements (4, 6, 8) so as to be movable relative to one another.

2. Electric motor rotor arrangement (2) according to claim 1, characterized in that the spring element (10, 12) is an elastomer spring (14, 16), preferably formed from a magnetically active elastomer.

3. Electric motor rotor arrangement (2) according to one of the preceding claims, characterized in that an inertial mass (18) is arranged on that one of the structural elements (4, 6, 8) which is arranged on the side of the spring element (10, 12) facing the central longitudinal axis (Z).

4. Electric motor rotor arrangement (2) according to one of the preceding claims, characterized in that the spring element (10, 12) forms a positive connection with at least one of the at least two structural elements (4, 6, 8).

5. Electric motor rotor arrangement (2) according to one of the preceding claims, characterized in that the spring element (10, 12) comprises at least one progression cavity (20).

6. Electric motor rotor arrangement (2) according to one of the preceding claims, characterized in that the spring element (10, 12) comprises a separating element (22) which separates the spring element (10, 12) into two radially adjacent spring element sections (10a, 10b).

7. Electric motor rotor arrangement (2) according to claim 6, characterized in that the spring element (10, 12) has at least one rib (36) projecting in the radial direction (R) and extending in the longitudinal direction (L), preferably the spring element (10, 12) has outer ribs (36a) projecting outwards radially and extending in the longitudinal direction (L) and / or inner ribs (36b) projecting inwards radially and extending in the longitudinal direction (L), and that at least one of the at least two structural elements (4, 6, 8) have a rib curvature (38a, 38b) corresponding to the rib (36), outer rib (36a) or inner rib (36b), into which the at least one rib (36), outer rib (36a) or inner rib (36b) projects, preferably an outer radial rib curvature (38a) and / or an inner radial rib curvature (38b). Electric motor rotor arrangement (2) according to claim 7, characterized in that the at least one rib curvature (38a, 38b) forms a curved path (40a, 40b) and / or a progression slope (42a, 42b) along which the rib (36), outer rib (36a) or inner rib (36b) can slide during relative movement in the circumferential direction (U) between one of the structural elements (4, 6, 8) which has the corresponding rib curvature (38a, 38b) and the spring element (10, 12) and is thereby subjected to an inward radial or outward radial force.Electric motor rotor arrangement (2) according to claims 7 and 8, characterized in that an air distance (44) is arranged in the circumferential direction (U) between a rib (36), outer rib (36a) or inner rib (36b) and the corresponding rib curvature (38a, 38b).

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