Rotor assembly with rotary locking of at least one disk element; and electric machine

Abstract

Rotor assembly (1) for an electric machine (10) of a hybrid or purely electric motor vehicle, comprising a rotor shaft (2), a magnet unit (4) mounted on a radial outer surface (3) of the rotor shaft (2) and non-rotatably connected to the rotor shaft (2), and at least two disk elements (5, 6) arranged axially next to the magnet unit (4), each of which is non-rotatably connected to the rotor shaft (2) by means of a spring-groove connection (7a, 7b), wherein an axially extending groove (9) of the rotor shaft (2) has a first longitudinal region (11a) having a first width in which the radially inwardly projecting nose (8a) of the first disk element (5) is received, and a second longitudinal region (11b) having a second width in which the radially inwardly projecting nose (8b) of the second disk element (6) is received, and the first width is different from the second width.

Description

[0001] The invention relates to a rotor assembly for an electric machine and to an electric machine itself, which is preferably used in a hybrid or purely electrically powered motor vehicle.

[0002] DE 11 2013 006 967 T5 describes a laminated rotor for electric drive trains in motor vehicles. DE 11 2010 004 773 T5 discloses a rotor assembly for an electric machine, comprising a rotor shaft, a magnet unit mounted on a radial outer side of the rotor shaft and connected in a rotationally fixed manner to the rotor shaft, and at least two disk elements arranged axially adjacent to the magnet unit, which are connected in a rotationally fixed manner to the rotor shaft by means of a tongue and groove connection.

[0003] One requirement for electrical machines and their rotor assemblies is to make the production and assembly of the corresponding components as simple as possible.

[0004] This is achieved according to the invention by the subject matter of claim 1. Accordingly, a rotor assembly for an electric machine of a hybrid or purely electrically powered motor vehicle is claimed, which has a rotor shaft, a magnet unit received on a radial outer side of the rotor shaft and connected in a rotationally fixed manner to the rotor shaft, and at least two disk elements arranged axially next to the magnet unit, wherein the disk elements are each connected in a rotationally fixed manner to the rotor shaft by means of a tongue and groove connection.

[0005] The tongue-and-groove connections between the rotor shaft and the respective disc elements allow the disc elements to be easily connected to the rotor shaft during assembly. The respective tongue-and-groove connections are also as simple to manufacture as possible. This also significantly reduces the manufacturing effort for the rotor assembly.

[0006] The axially extending groove of the rotor shaft has a first longitudinal region having a first width, in which a radially inwardly projecting (first) nose of a first disk element is received, and a second longitudinal region having a second width, in which a radially inwardly projecting (second) nose of a second disk element is received. Preferably, the second width (measured in the circumferential direction) of the second longitudinal region is greater than the first width (measured in the circumferential direction) of the first longitudinal region. This prevents incorrect assembly.

[0007] Further embodiments are claimed in the subclaims and explained in more detail below.

[0008] Accordingly, it is further advantageous if each disc element directly (preferably exclusively / only) has a radially inwardly projecting lug of the tongue-and-groove connection, which lug is inserted into an axially extending groove of the rotor shaft. This keeps the design of the tongue-and-groove connections as simple as possible. It is also expedient if the lugs of both disc elements are inserted into the same (partially continuous) groove of the rotor shaft. This further reduces manufacturing costs.

[0009] In other designs, the two noses of the two disc elements have a different shape in addition to or alternatively to the different width.

[0010] Furthermore, it is advantageous if at least one of the disk elements, more preferably each disk element, is supported on at least one axial side by an axial sleeve fixed to the rotor shaft. The axial sleeve is more preferably fixed directly to the outside of the rotor shaft by caulking. This keeps the number of components as low as possible.

[0011] It has also proven advantageous for a first disk element, which is attached to the rotor shaft by means of a first tongue and groove connection, to be designed as a balancing disk. This balancing disk preferably lies directly against an axial side of the magnet unit. This allows the balancing disk to be easily mounted on the rotor shaft.

[0012] If the first disc element is arranged axially between the magnet unit and the axial sleeve, the structure is further simplified.

[0013] Furthermore, it is advantageous if a second disk element, which is attached to the rotor shaft by means of a second tongue and groove connection, is designed as a sensor component for a rotor position sensor. This cleverly expands the functionality of the rotor assembly.

[0014] It is also advantageous if the second disc element is preloaded axially away from the axial sleeve via a disc spring and pressed against a retaining ring. This simultaneously allows for length compensation without significantly increasing manufacturing costs.

[0015] Furthermore, the invention relates to an electric machine for a hybrid or purely electrically driven motor vehicle, having a stator and a rotor assembly according to the invention, arranged radially inside the stator and rotatable relative to the stator according to at least one of the previously described embodiments.

[0016] In other words, the invention implements a rotational locking mechanism for a balancing disc and a stator (transmitter part) of a rotor position sensor. The rotating parts, e.g., the balancing disc or the transmitter part of the rotor position sensor, are secured to the rotor shaft by a projection forming a spring, which is inserted into a groove in the rotor shaft.

[0017] The invention will now be explained in more detail below with reference to figures.

[0018] They show: Fig. 1 a longitudinal sectional view of an electrical machine according to the invention comprising a rotor assembly designed according to a preferred embodiment, Fig. 2 a perspective view of the partially exploded rotor assembly from Fig. 1, wherein, among other things, two disc elements to be coupled to a rotor shaft via a tongue and groove connection are not yet pushed onto the rotor shaft, Fig. 3 a perspective view of the Fig. 1 and Fig. 2 inserted rotor shaft, Fig. 4 a perspective view of a Fig. 1 and Fig. 2 inserted, forming a balancing disc, first disc element, and Fig. 5 a perspective view of a Fig. 1 and Fig. 2 inserted second disc element forming a sensor part of a rotor position sensor.

[0019] The figures are merely schematic and serve solely to clarify the invention. The same elements are designated by the same reference numerals.

[0020] With Fig. Figure 1 initially shows the basic structure of an electric machine 10 according to the invention, as it is preferably used as a drive motor of a hybrid or purely electrically powered motor vehicle. The electric machine 10 typically has a stator 16 that is fixed to the housing and has a substantially annular shape overall. A rotor assembly 1 is mounted / received radially within the stator 16 along a central axis of rotation 17, rotatable relative to the stator 16. The structure of the rotor assembly 1 designed according to the invention is described in more detail below.

[0021] The rotor assembly has a rotor shaft 2. This rotor shaft 2, as with Fig. 1, is essentially realized in two parts. A magnet unit 4 of the rotor assembly 1 is fixed to a first tubular shaft part 18a of the rotor shaft 2. The magnet unit 4 is implemented as a laminated core, which is equipped with several magnets 19. The magnets 19 implemented as permanent magnets thus form a permanently magnetized magnet unit 4. As further described in connection with Fig. 3, the magnet unit 4 is fixed on a spline 20 formed on a (radial) outer side 3 of the rotor shaft 2.

[0022] In addition to the first shaft part 18a, the rotor shaft 2 has a second shaft part 18b, which is connected to the first shaft part 18a and directly adjoins this first shaft part 18a in the axial direction (i.e., along the rotational axis 17). In this exemplary embodiment, this second shaft part 18b has a helical gearing 21, by means of which gearing 21 the rotor shaft 2 is coupled to other output components during operation. The gearing 21 is arranged at an axial distance from the magnet unit 4 and the stator 16.

[0023] Furthermore, it can be seen that the magnet unit 4 is surrounded on its two axially opposite sides by corresponding disc elements 5, 22 in the form of balancing discs. A disc element arranged toward the axial side of the second shaft part 18b is designated as the third disc element 22 and, in this embodiment, is implemented as a balancing disc. This third disc element 22 is fixed directly to the spline 20.

[0024] A first disk element 5 is arranged on a side of the magnet unit 4 axially remote from the second shaft part 18b and is also implemented as a balancing disk.

[0025] How then especially well in connection with the Fig. 1 and Fig. 2, this first disk element 5 is connected to the rotor shaft 2 via a first tongue and groove connection 7a. The first tongue and groove connection 7a has a radially inwardly projecting first nose 8a on the side of the first disk element 5 as well as the groove 9 introduced on the side of the rotor shaft 2. The groove 9 is implemented as an axially extending groove and runs away from one end of the spline 20 in the axial direction. The groove 9 is open to an axial side facing away from the spline 20. As in connection with Fig. As can be clearly seen in Figure 4, only a first projection 8a is provided for implementing the first tongue-and-groove connection 7a. The first projection 8a has a first width (measured in the circumferential direction).

[0026] In addition to the first disk element 5, a further second disk element 6 is connected to the rotor shaft 2 by means of a second tongue and groove connection 7b. The second disk element 6 is realized in this embodiment as a sensor part / sensor wheel of a rotor position sensor. The second disk element 6, as then in connection with Fig. 5, has an outer contour 23 designed for speed measurement and / or rotational position measurement, which in this case is rosette-shaped. The outer contour 23 thus has several elevations 24 that are uniformly formed and of identical dimensions in the circumferential direction.

[0027] The second disc element 6 has a second projection 8b for implementing the second tongue-and-groove connection 7b. The second projection 8b has a second width (measured in the circumferential direction). The groove 9 of the second tongue-and-groove connection 7b is the same groove 9 as in the first tongue-and-groove connection 7a. The two tongue-and-groove connections 7a, 7b thus have the same groove 9, which is incorporated into the rotor shaft 2.

[0028] As in connection with the Fig. 2 and Fig. 3, the groove 9 has two different longitudinal regions 11a, 11b which differ from one another in terms of their width (measured in the circumferential direction). The width of a first longitudinal region 11a essentially corresponds to the (first) width of the first lug 8a, whereas the width (measured in the circumferential direction) of a second longitudinal region 11b essentially corresponds to the (second) width of the second lug 8b. In this embodiment, the second width of the second lug 8b is greater than the first width of the first lug 8a. Consequently, the width of the second lug 8b is greater than the width of the first longitudinal region 11a. In this context, it should also be noted that in further embodiments the lugs 8a, 8b can not only be dimensioned differently in their width, but also have different shapes.

[0029] In connection with the Fig. 1 and Fig.2 also shows the axial fixation of the two disc elements 5, 6 to the rotor shaft 2. In this context, it is clear that after the first disc element 5 has axially engaged the magnet unit 4, it is secured in its axial position by an axial sleeve 12. The axial sleeve 12 is fixed to the rotor shaft 2 by means of caulking. The axial sleeve 12 thus serves to directly engage / support a first axial side 13a (the side axially facing away from the magnet unit 4) of the first disc element 5.

[0030] The second disk element 6 is supported on the axial sleeve 12 with a second axial side 13b (the side axially facing the magnet unit 4). This support is provided indirectly via a disc spring 14, which is axially compressible. This disc spring 14 bears against the second disk element 6 in such a way that it is pressed axially against a retaining ring 15. The retaining ring 15 is, in turn, typically fixed in an annular groove 25 of the rotor shaft 2.

[0031] In other words, the inventive designs of the balancing disc 5 and the stator 6 of the rotor position sensor with a drive tooth 8a, 8b allow these components to be secured simply and cost-effectively using a keyway connection 7a, 7b. Components 5, 6 are preferably secured using different groove widths. In other embodiments, identical groove widths are also provided.

[0032] During machining, shaft 2 is provided with a keyed connection designed to accommodate the components (balancing disc 5 and stator 6 of the rotor position sensor) and secure them against rotational rotation on shaft 2. Components 5 and 6 each have a driving tooth 8a and 8b for this purpose, which can be identical or vary in shape as required. The axial securing of the components is achieved independently of one another by separate elements, but can also be fixed independently of one another by a single corresponding spring element.

[0033] In this case, the axial sleeve 12 is used to secure the balancing disc 5 against the rotor core 4 and the second balancing disc 22. The sleeve 12 is axially fixed to the shaft 2 by radial caulking. The disc spring 14 is used to press the stator 6 of the rotor position sensor axially against the retaining ring 15. The disc spring 14 also simultaneously performs the function of length compensation. List of reference symbols 1 rotor assembly 2 rotor shaft 3 Outside 4 Magnet unit 5 first disc element 6 second disc element 7a first tongue and groove connection 7b second tongue and groove connection 8a first nose 8b second nose 9 grooves 10 electric machine 11a first longitudinal section 11b second longitudinal area 12 Axial sleeve 13a first axial side 13b second axial side 14 disc spring 15 Retaining ring 16 Stator 17 axis of rotation 18a first shaft part 18b second shaft part 19 Magnet 20 spline 21 Helical gearing 22 third disc element 23 Outer contour 24 Survey 25 ring groove

Claims

[1] Rotor assembly (1) for an electric machine (10) of a hybrid or purely electrically powered motor vehicle, comprising a rotor shaft (2), a magnet unit (4) received on a radial outer side (3) of the rotor shaft (2) and connected in a rotationally fixed manner to the rotor shaft (2), and at least two disk elements (5, 6) arranged axially next to the magnet unit (4), each of which is connected in a rotationally fixed manner to the rotor shaft (2) by means of a tongue and groove connection (7a, 7b), wherein an axially extending groove (9) of the rotor shaft (2) has a first longitudinal region (11a) having a first width, in which the radially inwardly projecting nose (8a) of the first disk element (5) is received, a second longitudinal region (11b) having a second width, in which the radially inwardly projecting nose (8b) of the second disk element (6) is received, and the first width is different from the second width. [2] Rotor assembly (1) according to one of claims 1, characterized by that at least one of the disc elements (5, 6) is supported towards at least one axial side (13a, 13b) by an axial sleeve (12) fixed on the rotor shaft (2). [3] Rotor assembly (1) according to one of claims 1 and 2, characterized by that a first disc element (5), which is fastened to the rotor shaft (2) by means of a first tongue and groove connection (7a), is designed as a balancing disc. [4] Rotor assembly (1) according to claim 3, characterized by that the first disc element (5) is arranged axially between the magnet unit (4) and the axial sleeve (12). [5] Rotor assembly (1) according to one of claims 1 to 4, characterized by that a second disc element (6), which is fastened to the rotor shaft (2) by means of a second tongue and groove connection (7b), is designed as a sensor part for a rotor position sensor. [6] Rotor assembly (1) according to claim 5, characterized bythat the second disc element (6) is preloaded axially away from the axial sleeve (12) via a disc spring (14) and pressed against a retaining ring (15). [7] Electric machine (10) for a hybrid or purely electrically driven motor vehicle, comprising a stator (16) and a rotor assembly (1) according to one of claims 1 to 6, arranged radially inside the stator (16) and rotatable relative to the stator (16).

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