Electric machine with an axial spring element

Abstract

Electric machine (1), especially for use in a motor vehicle, comprising: - a rotor (5) with a rotor shaft (51) and a rotor body (52) arranged thereon; - a housing part (2) with a bearing (4) for receiving the rotor shaft (51) of the rotor (5); - an elastic axial spring element (6) arranged between the bearing (4) and the rotor body (52) on the rotor shaft (51);wherein the spring element (6) has one or more retaining elements (64) at its end facing the rotor body (52) in the axial direction, with which the end facing the rotor body (52) can be clamped so that the spring element (6) is held on the rotor body (52), wherein the axial spring element (6) has two circumferential ring elements (61, 62) spaced apart from each other in the axial direction and which are elastically connected to each other, wherein at least one of the ring elements (61) has the one or more retaining elements (64), wherein the one or more retaining elements (64) are each formed with a retaining claw which projects radially outwards from the respective ring element (61), wherein the ring element (61) on which the one or more retaining elements (64) are arranged is larger than the further ring element (62), and wherein the corresponding retaining claws extend obliquely axially towards the further ring element (62) and the bearing (4). protrude;

Description

Technical area

[0001] The invention relates generally to rotary electrical machines, in particular electrical machines in which an axial spring element is arranged between the rotor body and the bearing of the rotor shaft. State of the art

[0002] In electrical machines with an internal rotor, a rotor body carrying a rotor armature is usually mounted on a rotor shaft. The rotor shaft is mounted in a housing of the electrical machine by means of appropriate ball bearings.

[0003] From the document JP 2000 30 8305 A it is also known that a washer is arranged between a ball bearing and the rotor body on the rotor shaft, which supports the rotor axially relative to the ball bearing. The washer is designed as a spring element with an annular part, on which radially projecting spring parts are formed, which are resiliently supported on the rotor armature. From the document DE 10 2004 041 074 A1 an electrical machine is known in which the axial spring element is firmly attached to the rotor armature. The machine has a housing part with a bearing in which the rotor shaft is accommodated. The spring element is arranged between the bearing and the rotor body and is clamped in the rotor body by a radially circumferential outer wall.

[0004] DE 10 2008 040 700 A1, DE 299 01 278 U1, and WO 01 / 16499 A1 disclose electrical machines in which rotor components are mounted in a housing, eliminating axial play. DE 103 442 20 A1 discloses a press-fit ring with a sleeve portion and a spring element attached to it for accommodating a bearing. Disclosure of the invention

[0005] According to the invention, a rotary electrical machine according to claim 1 and a method for assembling the electrical machine according to the independent claim 4 are provided.

[0006] Further advantageous embodiments of the present invention are specified in the dependent claims.

[0007] According to a first aspect, an electrical machine is provided with an axial spring element having two circumferential ring elements spaced apart from one another in the axial direction and connected to one another in a spring-elastic manner, wherein at least one of the ring elements has one or more holding elements in order to clamp the spring element to a rotor and thereby hold the spring element to the rotor.

[0008] One idea behind the above axial spring element is to ensure secure, yet simple and robust installation of the spring element when building an electrical machine. In the prior art, structural changes to the design of the rotor, particularly the rotor body, were necessary to secure the axial spring element firmly to the rotor body. This led to modifications and / or increased design effort for the components relating to the rotor, particularly the rotor body. Therefore, the above axial spring element is designed to be connected to the rotor without any structural changes to the rotor body or rotor shaft being necessary. At the same time, however, it is ensured that the axial spring element can also be applied to a vertical rotor shaft and can be connected to the rotor in such a way that it cannot become detached from the rotor.

[0009] For this purpose, the axial spring element features resilient retaining elements on its outer part, which are press-fitted to the rotor, particularly to an insulating lamella of the rotor body or rotor shaft. This allows axial fixation of the spring element without having to modify rotor components. Furthermore, the elastic retaining elements have the advantage that tolerances resulting from manufacturing and assembly can be compensated. The clamping connection between the retaining elements of the spring element and the rotor allows acceleration forces of the rotor to be transmitted directly to the spring element, thus preventing relative movement in the form of slippage between the rotor and the spring element during motor operation.

[0010] It is further provided according to the invention that the one or more holding elements are each formed with a holding claw which protrudes radially outwards from the respective ring element.

[0011] According to the invention, the ring element on which the one or more holding elements are arranged is larger than another of the ring elements, wherein the corresponding holding claws protrude obliquely in the direction of the further ring element.

[0012] According to the invention, the electrical machine, in particular for use in a motor vehicle, comprises: - a rotor with a rotor shaft and a rotor body arranged thereon; - a housing part with a bearing for receiving the rotor shaft of the rotor; - an elastic spring element arranged on the rotor shaft between the bearing and the rotor body; wherein the spring element has one or more holding elements at its end facing the rotor body in the axial direction, with which the end facing the rotor body can be clamped so that the spring element is held on the rotor body.

[0013] Furthermore, the rotor body can be provided with a cylindrical inner recess into which the spring element is inserted.

[0014] It can be provided that the inner recess is formed by a hollow cylindrical insulating lamella on which an anchor package of anchor lamellas is applied.

[0015] According to a further aspect, a method for assembling an electrical machine is provided, wherein, before inserting a rotor into a housing part, the above spring element is pushed onto a rotor shaft of the rotor, at least until the holding element(s) secures the spring element against falling out, and wherein the rotor with the spring element is subsequently inserted into the housing part, so that the rotor shaft is held by the bearing. Brief description of the drawings

[0016] Preferred embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. They show: Fig. 1 an exploded view of an electrical machine; Fig. 2A to 2C are views of the axial spring element according to an embodiment; Fig. 3 a perspective view of a rotor with inserted spring element; Fig. 4 a plan view in axial direction of the rotor with inserted spring element, Fig. 5 a view of the axial spring element according to an embodiment not according to the invention. Description of embodiments

[0017] In Fig. Figure 1 shows a perspective exploded view of a portion of an electrical machine 1. In the present exemplary embodiment, the electrical machine 1 corresponds to an internal rotor electric motor. The electrical machine 1 comprises a housing part 2, which is designed as a pole pot. The pole pot can be formed integrally from a metallic material, e.g., by deep drawing or a comparable manufacturing process.

[0018] The housing part 2 has a circular-cylindrical recess 3 at one end, in which a bearing 4 in the form of a ball or roller bearing can be accommodated. In the assembled state, the bearing 4 is fully or partially accommodated in the recess 3 and held against slipping, at least in the radial direction, by the circumferential wall of the recess 3. The bearing 4 is conventionally designed with an inner part 41 and an outer part 42, which are arranged so as to be rotatable relative to one another by rollers or balls (not shown). The inner part 41 has a through-opening 43 concentric with the outer circumference of the bearing 4.

[0019] Furthermore, a rotor 5 is provided, which has a rotor body 52 connected to a rotor shaft 51. The rotor body 52 further comprises a rotor armature 55, which is attached to the rotor shaft 51. Between the rotor shaft 51 and the rotor armature 52, a substantially cylindrical insulating part 53 can be provided, which defines a substantially circular-cylindrical inner recess 54. The rotor armature 52 is designed, for example, as a lamination pack that is mounted on the insulating part 53.

[0020] An elastic spring element 6 is arranged between the bearing 4 and the rotor 5 to axially brace the rotor shaft 51 relative to the bearing 4. The spring element 6 is supported on the one hand by the inner part 41 of the bearing 4 and on the other hand by the rotor body 52.

[0021] As in the views of the Fig. As shown in Figures 2a to 2c, the spring element 6 has an inner ring 61 and an outer ring 62, which are designed concentrically to receive the rotor shaft 51 and are axially offset from one another. The inner ring 61 and the outer ring 62 are connected to one another via webs 63 that are spiral-shaped or at least arranged obliquely to the radial direction. The webs 63 are designed such that they enable an axially resilient displacement of the inner ring 61 and the outer ring 62 relative to one another in order to provide a spring travel in the axial direction. In the exemplary embodiment shown, three webs 63 are provided; however, the number of webs 63 is essentially arbitrary, as long as the axial resilience between the inner ring 61 and the outer ring 62 is ensured.

[0022] The axial spring element 6 is manufactured, for example, as a stamped and bent part made of spring steel and can have stiffeners of a suitable shape in order to prevent bending of the inner ring 61 or the outer ring 62.

[0023] In the Fig. In the embodiment shown in Figures 2a to 2c, the outer ring 62 has protruding retaining claws 64 on its outer circumference as elastic retaining elements, with which the spring element 6 can be pressed into the inner recess 54, so that the retaining claws 64 press against a circumferential inner wall of the inner recess 54 and thus secure the spring element 6 against falling out of the inner recess 54. In the unassembled state, the outer ends of the retaining claws 65 define a diameter that is larger than the diameter of the rotor shaft 51.

[0024] The retaining claws 64 are preferably arranged distributed around the circumferential direction of the outer ring 62. The number of retaining claws 64 is preferably three, but only two or more than three retaining claws 64 may be provided.

[0025] The retaining claws 64 preferably protrude radially outwards and obliquely in the direction of the inner ring 61, ie in the direction of the bearing 4. In this way, during assembly of the electrical machine 1, it is easily possible to insert the spring element 6 into the rotor recess 54 until the retaining claw 64 clamps itself against the inner surface of the insulating lamella 53 and thus ensures a reliable fit of the spring element 6.

[0026] In the Fig. 3 and Fig. Figure 4 shows various views of a spring element 6 inserted into the inner recess 54 of the rotor 5. It can be seen that the outer ends of the retaining claw 64 rest against the inner wall of the inner recess 54 and thus hold the spring element 6 concentrically to the rotor shaft 51.

[0027] To assemble the electric machine 1, the axial spring element 6 is fixed at least axially to the pre-assembled rotor 5 by being inserted into the inner recess 54. The retaining claws 64 reliably hold the spring element 6 on the rotor 5, so that the rotor 5 can also be inserted overhead by means of so-called blind assembly into the bearing 4 previously mounted in the housing part 2. The axial assembly force allows the axial preload of the spring element 6 to be adjusted. In the event of thermal expansion during operation, the rotor body 52 can then be displaced relative to the housing part 2 while maintaining an axial clamping force, without the spring element 6 becoming wedged on the rotor shaft 51.

[0028] According to an embodiment not according to the invention, which is shown in Fig.5, the holding elements can also be designed in the form of holding claws 65 extending radially inward, which are arranged on the outer ring 62. In this embodiment, too, the holding claws are preferably designed to extend obliquely in the direction of the inner ring 61. In the unassembled state, the inner ends of the holding claws 65 define a diameter that is smaller than the diameter of the rotor shaft 51. In this case, the holding claws 65 can clamp onto the rotor shaft 51 during assembly.

Claims

[1] Electrical machine (1), in particular for use in a motor vehicle, comprising: - a rotor (5) with a rotor shaft (51) and a rotor body (52) arranged thereon; - a housing part (2) with a bearing (4) for receiving the rotor shaft (51) of the rotor (5); - an elastic axial spring element (6) arranged between the bearing (4) and the rotor body (52) on the rotor shaft (51);wherein the spring element (6) has, at its end facing the rotor body (52), one or more holding elements (64) in the axial direction, with which the end facing the rotor body (52) can be clamped such that the spring element (6) is held on the rotor body (52), wherein the axial spring element (6) has two circumferential ring elements (61, 62) spaced apart from one another in the axial direction and connected to one another in a spring-elastic manner, wherein at least one of the ring elements (61) has the one or more holding elements (64), wherein the one or more holding elements (64) are each formed with a holding claw that projects outwardly in the radial direction from the respective ring element (61), wherein the ring element (61) on which the one or more holding elements (64) are arranged is larger than the further ring element (62), and wherein the corresponding holding claws are arranged obliquely axially in the direction of the further ring element (62) and the bearing (4). stand out.; [2] Electrical machine (1) according to claim 1, wherein the rotor body (52) is provided with a cylindrical inner recess (54) into which the spring element (6) is inserted. [3] Electrical machine (1) according to claim 1 or 2, wherein the inner recess (54) is formed by a hollow cylindrical insulating lamella (53) on which an armature package of armature lamellas is applied. [4] Method for assembling an electrical machine (1), wherein, before inserting a rotor (5) into a housing part (2), a spring element (6) according to one of claims 1 to 3 is pushed onto a rotor shaft (51) of the rotor (5), at least until the holding element(s) (64) secures the spring element (6) against falling out, and wherein the rotor (5) with the spring element (6) is then inserted into the housing part (2) so that the rotor shaft (51) is held by the bearing (4).

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