Stator for an electric machine, electric machine and machine-gear arrangement

Abstract

The present invention relates to a stator (100; 100*) for an electric machine (200), comprising an annular stator body (1; 1*) and several stator windings (2) arranged on the stator body (1; 1*), wherein the stator body (1; 1*) comprises at least one annular segment (1.1) extending along a circular path (K) and at least one indentation segment (1.2) having a radially inward orientation relative to the circular path (K), and wherein the stator windings (2) are arranged on the at least one annular segment (1.1). The present invention further relates to an electric machine (200) comprising: a stator (100; 100*) according to the invention, and a rotor (201) rotatably arranged within the stator body (1; 1*) about a rotor axis of rotation (R).The present invention further relates to a machine-gear arrangement (300) comprising: an electric machine (200) according to the invention, a first gear (301) arranged to rotate with the rotor (201), a second gear (302) arranged to engage with the first gear (301), and an element (303) which is non-rotatably connected to the second gear (302), wherein the element (303) is arranged at least partially in a region (B) between a recessed segment (1.2) and the circular path (K).

Description

[0001] The present invention relates to a stator for an electric machine, comprising an annular stator body and several stator windings arranged on the stator body. The present invention further relates to an electric machine comprising: such a stator, and a rotor rotatably arranged within the stator body about a rotor axis of rotation. The present invention further relates to a machine-gear assembly comprising: such an electric machine, a first gear arranged to rotate with the rotor, a second gear arranged in mesh with the first gear, and an element, for example, a gear shaft or a third gear, which is non-rotatably connected to the second gear.

[0002] Such a machine-gear arrangement is known from DE 10 2023 101 992 A1.

[0003] The present invention is based on the objective of enabling a relatively free and space-saving design of a gear stage formed by the first gear and the second gear in a machine-gear arrangement of the type mentioned above.

[0004] This problem is solved according to the invention by a stator for an electric machine with the features of claim 1, by an electric machine with the features of claim 12, and by a machine-gear arrangement with the features of claim 13.

[0005] The stator according to the invention for an electric machine comprises an annular stator body, i.e., a stator body rotating around a central point. The stator body can, in principle, have any shape, as long as it forms a complete circuit. Preferably, the stator body forms a closed, uninterrupted circuit. However, it is also conceivable that the circuit has an interruption. According to the invention, the stator body in any case comprises at least one annular segment extending along a circular path and at least one indentation segment having a radially inward course deviating from the circular path. The stator body thus comprises at least one substantially annular section, the at least one annular segment, and at least one section that deviates from the circular shape, specifically being radially inwardly recessed, the at least one indentation segment.If the stator body comprises several circular segments, these preferably all extend along the same circular path. The at least one indentation segment can, in principle, have any radially inward path deviating from the circular path of the at least one circular segment, for example, a straight path or a radially inward-directed V- or U-shaped path. The stator body consists of a magnetizable material, preferably a ferromagnetic one. The stator body can, in principle, be designed as either a monolithic solid or as a laminated core.

[0006] The stator according to the invention for an electric machine further comprises several, preferably six, stator windings designed in a generally known manner for generating a magnetic field that drives a rotor of the electric machine. According to the invention, the stator windings are arranged concentrically to the center point of the circular path along which the at least one annular segment runs, and are located on the at least one annular segment of the stator body. Thus, according to the invention, the stator windings are arranged adjacent to the at least one annular segment of the stator body. At least the central axes of all stator windings are therefore located within the angular region of the at least one annular segment, the angular region being defined by the center point of the circular path. Preferably, the stator windings are located entirely within the angular region of the at least one annular segment.If the stator body comprises several annular segments, the stator windings are preferably arranged evenly distributed across these segments, meaning that preferably an equal number of stator windings are arranged adjacent to each annular segment. Preferably, all stator windings have the same number of turns. However, it is also conceivable that the stator windings have different numbers of turns.

[0007] Because the stator body comprises at least one indentation segment, the element of a machine-gear assembly of the type mentioned above, which is rotationally fixed to the second gear and realized with the stator according to the invention, can be arranged relatively close to the center of the circular path along which the at least one annular segment runs, and thus relatively close to an axis of rotation of a rotor of the machine-gear assembly. This allows the use of gears with a relatively small diameter for the first and second gears of the machine-gear assembly and thus a relatively free design of a gear stage formed by the first and second gears.

[0008] Preferably, the stator body is rotationally symmetrical with respect to the center point of the circular path, so that the stator can be installed in several orientations, which is advantageous for handling the stator body during assembly. Particularly preferably, the stator body is additionally mirror-symmetrical with respect to a mirror plane passing through the center point of the circular path and intersecting the circular path.

[0009] In a preferred embodiment, the stator body comprises two opposing annular segments and two opposing indentation segments. Preferably, both the annular segments and the indentation segments have the same shape to create a symmetrical stator body that is easy to handle during assembly. The stator windings are preferably arranged in two stator winding groups, with one of the two stator winding groups being arranged on each annular segment. Preferably, the two stator winding groups have the same number of stator windings, particularly preferably three stator windings each. This enables relatively uniform driving of the rotor of an electric machine implemented with the stator according to the invention, despite the two indentation segments not having stator windings.

[0010] Preferably, the stator body is designed as a laminated core to reduce eddy current losses, i.e., it is formed from a multitude of stacked and interconnected, preferably identically shaped, laminated parts.

[0011] In a preferred embodiment, at least one radially inwardly projecting magnetic field guidance element is formed on the at least one indentation segment of the stator body. This at least one magnetic field guidance element is integrally formed with the stator body, i.e., it is formed either by the same monolithic solid body or by the same laminated core as the stator body. Preferably, several magnetic field guidance elements are formed on each indentation segment. Preferably, all magnetic field guidance elements have the same radial distance to the center of the circular path as the stator teeth supporting the stator windings. With the at least one magnetic field guidance element, an improved magnetic field distribution in the stator of an electric machine implemented with the stator according to the invention can be achieved compared to a stator without magnetic field guidance elements.

[0012] Preferably, the stator teeth, which support the stator windings, are integrally formed with the stator body. This means that, in the case of a stator body designed as a monolithic solid, the stator teeth are formed in one piece with the stator body, i.e., by the same monolithic solid. Similarly, in the case of a stator body designed as a laminated core, the stator teeth are formed by the same laminated core, i.e., by the same laminations, as the stator body. During assembly, the stator windings can either be applied directly to the stator teeth, preferably by means of needle winding, or wound onto a carrier and slid onto the stator teeth. However, it is also conceivable that separate stator teeth, preferably already equipped with a stator winding, can be attached to the stator body.

[0013] In a preferred embodiment, the stator windings are arranged in several stator winding groups, wherein circumferentially adjacent stator windings within a stator winding group have an angular distance from each other that is smaller than the angular distance between circumferentially adjacent stator windings of different stator winding groups. The angular distance here is understood to be the circumferential distance between the centerlines of the two stator windings under consideration, with the circumferential direction referring to the circular path along which the at least one annular segment runs.

[0014] In principle, circumferentially adjacent stator windings of a stator winding group can have an angular spacing in the range of 30° to 60°. Preferably, however, instead of the 30° angular spacing typical for a conventional stator with twelve stator windings distributed along the entire circumference of the stator body, the circumferentially adjacent stator windings of a stator winding group have an angular spacing in the range of 32.5° to 40°. This makes it possible to increase the cogging torque of the rotor in an electric machine implemented with the stator according to the invention, thus creating a self-locking electric machine. Additionally, the larger angular spacing also allows the use of stator windings with a greater number of turns.

[0015] In a preferred embodiment, the stator according to the invention additionally comprises a plastic body formed by overmolding the stator body. The plastic body typically serves as electrical insulation between the stator windings and the stator teeth that support them. Furthermore, in a stator body designed as a laminated core, the plastic body also reliably holds the laminated core components together. Alternatively, it is also conceivable that the plastic body could be implemented as two half-shells that are slid onto the stator body.

[0016] Typically, the stator according to the invention additionally comprises several contact elements for electrically contacting the stator windings. In principle, the contact elements can be arranged at any location on the stator. Preferably, however, the contact elements are arranged in the angular region of a recessed segment, with each contact element preferably being at least partially located in a region between the respective recessed segment and the circular path. This allows for a space-saving arrangement of the contact elements.

[0017] If the stator comprises a previously described plastic body, the contact elements are preferably attached to the plastic body. Particularly preferably, the contact elements are embedded in the plastic body, i.e., overmolded by the plastic body, or pressed into the plastic body, and thus reliably attached to it.

[0018] The electric machine according to the invention comprises a stator according to the invention and a rotor, which is rotatably arranged about a rotor axis in the stator body of the stator according to the invention. The rotor preferably comprises one or more permanent magnets which, during operation of the electric machine according to the invention, interact with a magnetic field generated by the stator windings. The rotor axis of rotation preferably extends through the center of the circular path along which the at least one annular segment of the stator body extends.

[0019] The electric machine according to the invention enables, through the stator according to the invention, a relatively free and space-saving design of the gear stage formed by the first gear and the second gear in a machine-gear arrangement realized with the electric machine according to the invention.

[0020] The machine-gear arrangement according to the invention comprises an electrical machine according to the invention with a stator according to the invention.

[0021] The machine-gear arrangement according to the invention further comprises a first gear which is arranged to rotate with the rotor of the electric machine according to the invention. Preferably, the first gear is arranged coaxially with the rotor.

[0022] The machine-gear arrangement according to the invention further comprises a second gear which is arranged in mesh with the first gear, thus forming a gear stage together with the first gear, specifically a spur gear stage. Preferably, the second gear has a larger diameter and therefore a greater number of teeth than the first gear.

[0023] The machine-gear assembly according to the invention further comprises an element that is rotationally fixed to the second gear. The element is preferably formed integrally, i.e., monolithically, with the second gear, but can also be a separate component rotationally fixed to the second gear. The element can, for example, be a third gear or a gear shaft on which the second gear is mounted. According to the invention, the element is arranged at least partially in a region between a recessed segment of the stator according to the invention and the circular path along which the at least one annular segment of the stator according to the invention runs.As previously described, this makes it possible to position the element relatively close to the axis of rotation of the rotor, which in turn allows the use of gears with a relatively small diameter and thus a relatively free design of the gear stage formed by the first gear and the second gear.

[0024] An embodiment of the present invention is described below with reference to the accompanying figures. These show: Fig. 1 a schematic top view of a stator according to the invention, Fig. 2 a schematic exploded view of the stator made of Fig. 1 to Fig. 3, Fig. 3 a schematic top view of a stator body of the stator made of Fig. 1 and Fig. 2, Fig. 4 a schematic perspective view of an electrical machine according to the invention, the stator of which Fig. 1 to Fig. 3 includes, Fig. 5 a schematic perspective view of a machine-gear arrangement according to the invention, comprising the electric machine Fig. 4 includes, Fig. 6 a schematic top view of an alternative stator according to the invention, and Fig. 7 a schematic top view of a stator body of the stator made of Fig. 6.

[0025] Fig. 1 to Fig. Figure 5 shows a stator 100 according to the invention for a Fig. 4 and Fig. 5 shown in the invention, electrical machine 200.

[0026] The stator 100 comprises a ring-shaped stator body 1, which is designed as a laminated core, i.e., consists of a large number of stacked laminated parts, not shown individually here.

[0027] The stator body 1 comprises two opposing circular ring segments 1.1, each extending along a Fig. 3 dashed circular path K run, as well as two opposing indentation segments 1.2, each of which has a course deviating from the circular path K radially inwards, i.e. in the direction of a center point M of the circular path K.

[0028] The stator body 1 further comprises six integrally formed stator teeth 1.3 projecting radially inwards from the two annular segments 1.1, wherein three stator teeth 1.3 are formed on each of the two annular segments 1.1.

[0029] The stator teeth 1.3 are arranged on the circular ring segments 1.1 in such a way that the central axes of adjacent stator teeth 1.3 arranged on the same circular ring segment 1.1 each run at an angular distance W1 of 35° to each other.

[0030] The stator body 1 is rotationally symmetrical with respect to the center point M of the circular path K.

[0031] The stator 100 further comprises six stator windings 2, which are arranged on the stator body 1, specifically on the stator teeth 1.3 formed on the annular segments 1.1 of the stator body 1, wherein each of the stator windings 2 is arranged on one of the stator teeth 1.3 and held by the respective stator tooth 1.3 such that the central axes of the stator windings 2 correspond to the central axes of the stator teeth 1.3.

[0032] The stator windings 2 are therefore arranged in two stator winding groups 3, wherein each stator winding group 3 comprises those three stator windings 2 that are arranged together on one of the two circular ring segments 1.1.

[0033] In this case, the circumferentially adjacent stator windings 2 of a stator winding group 3 each have an angular distance W1 to each other, and the two outermost stator windings 2 of one stator winding group 3 have an angular distance W2 of 110° to the circumferentially adjacent stator winding 2 of the other stator winding group 3.

[0034] The stator 100 further comprises a plastic body 4, which is formed by overmolding the stator body 1, wherein the plastic body 4 holds together the stator body 1 designed as a laminated core and furthermore electrically insulates the stator body 1 from the stator windings 2.

[0035] The stator 100 further comprises three contact elements 5 for external electrical contacting of the stator windings 2, wherein the contact elements 5 are located in an angular range WB of the representation in Fig. 1 lower indentation segment 1.2 of the stator body 1 are embedded in the plastic body 4, wherein the contact elements 5 are also overmolded by the plastic body 4.

[0036] The in Fig. 4 and Fig. The electrical machine 200 shown in Figure 5 according to the invention comprises, in addition to the stator 100, a permanent magnet rotor 201, which includes a rotor shaft 201.1, and which is rotatably arranged within the stator body 1 of the stator 100 about a rotor rotation axis R passing through the center point M of the circular path K.

[0037] Fig. Figure 5 shows a machine-gear arrangement 300 according to the invention, realized with the electric machine 200 according to the invention.

[0038] The machine-gear arrangement 300 comprises a first gear 301, which is attached to the rotor shaft 201.1 of the rotor 201 and is thus arranged to rotate with the rotor 201.

[0039] The machine-gear arrangement 300 further comprises a second gear 302, which is rotatable about an axis of rotation D and is arranged in engagement with the first gear 301.

[0040] An element 303, which in the present embodiment is a third gear, is attached or integrally formed on the second gear 302, wherein the element 303 is at least partially embedded in a Fig. 3 marked area B between the one relating to the representation in Fig. 3 upper indentation segment 1.2 of the stator body 1 and the circular path K is arranged.

[0041] Fig. Figure 6 shows another stator 100* according to the invention and Fig. Figure 7 shows a stator body 1 * of the stator 100*, wherein, for the description of the stator 100* or the stator body 1 *, the corresponding features from are known to be identical or similar to those of the stator 100 or of the stator body 1. Fig. 1 to Fig.5 can be used.

[0042] The stator 100* differs from the stator 100 essentially in that, in the stator body 1 *, three integral magnetic field guidance elements 1.4 are formed on each of the two indentation segments 1.2, projecting radially inwards, i.e. in the direction of the center M of the circular path K, wherein the central axes of adjacent magnetic field guidance elements 1.4 each have an angular distance W3 of 30° to each other.

[0043] The stator 100* also differs from the stator 100 in that the stator windings 2 to a neighboring stator winding 2 or to a neighboring magnetic field guiding element 1.4 also each have the angular distance W3. Reference symbol list 100; 100* Stator 1; 1 * Stator body 1.1 Circular ring segments 1.2 Indentation segments 1.3 Stator teeth 1.4 Magnetic field guiding elements 2 stator windings 3 stator winding groups 4 plastic bodies 5 contact elements 200 electric machine 201 Rotor 201.1 Rotor shaft 300 machine-gear arrangement 301 first gear 302 second gear 303 Gear shaft Area B D axis of rotation K circular track R Rotor axis W1 angular distance W2 angular distance W3 angular distance WB angle range QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2023 101 992 A1

[0002]

Claims

[1] Stator (100; 100*) for an electric machine (200), comprising a ring-shaped stator body (1; 1 *) and several stator windings (2) arranged on the stator body (1; 1 *), characterized by , that the stator body (1; 1 *) comprises at least one annular segment (1.1) extending along a circular path (K) and at least one indentation segment (1.2) having a radially inward course deviating from the circular path (K), wherein the stator windings (2) are arranged on the at least one annular segment (1.1). [2] Stator (100; 100*) according to claim 1, wherein the stator body (1; 1 *) is rotationally symmetric with respect to a center point (M) of the circular path (K). [3] Stator (100; 100*) according to one of the preceding claims, wherein the stator body (1; 1 *) comprises two opposing circular ring segments (1.1) and two opposing indentation segments (1.2). [4] Stator (100; 100*) according to one of the preceding claims, wherein the stator body (1; 1 *) is designed as a laminated core. [5] Stator (100*) according to one of the preceding claims, wherein at least one radially inwardly projecting magnetic field guidance element (1.4) is formed on the at least one indentation segment (1.2). [6] Stator (100; 100*) according to one of the preceding claims, wherein the stator windings (2) supporting stator teeth (1.3) are integrally formed with the stator body (1; 1 *). [7] Stator (100; 100*) according to one of the preceding claims, wherein the stator windings (2) are arranged in several stator winding groups (3), wherein circumferentially adjacent stator windings (2) of a stator winding group (3) have an angular distance (W1; W3) to each other which is less than an angular distance (W2) between circumferentially adjacent stator windings (2) of different stator winding groups (3). [8] Stator (100) according to claim 7, wherein circumferentially adjacent stator windings (2) of a stator winding group (3) have an angular distance (W1) to each other in the range of 32.5° to 40°. [9] Stator (100; 100*) according to one of the preceding claims, further comprising a plastic body (4) formed by overmolding the stator body (1; 1*). [10] Stator (100; 100*) according to one of the preceding claims, further comprising several contact elements (5) for electrical contacting the stator windings (2), wherein the contact elements (5) are arranged in the angular region (WB) of a recess segment (1.2). [11] Stator (100; 100*) according to claims 9 and 10, wherein the contact elements (5) are attached to the plastic body (4). [12] Electric machine (200) comprising: a stator (100; 100*) according to one of the preceding claims, and a rotor (201) which is rotatably arranged within the stator body (1; 1 *) about a rotor rotation axis (R). [13] Machine-gear arrangement (300) comprising: an electric machine (200) according to claim 12, a first gear (301) which is arranged to rotate with the rotor (201), a second gear (302) which is arranged in engagement with the first gear (301), and an element (303) which is non-rotatably connected to the second gear (302), wherein the element (303) is at least partially located in a region (B) between an indentation segment (1.2) and the circular path (K).

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