Stator for an electric motor

Abstract

A stator (1) for an electric motor has a modular stator body (2) with at least two stator cores (10, 20) arranged axially in series. Each core (10, 20) is form from a plurality of stacked electrical laminations (11, 21). This forms winding poles (16, 26) with radially extending winding webs (17, 27). The stator cores (10, 20) each have a separate overmolding (U1, U2).

Claims

1. A stator for an electric motor comprising: a modular stator body including at least two stator cores arranged axially in series in electrical contact, each stator core is formed from a plurality of stacked electrical laminations that form winding poles with radially extending winding webs; the stator cores each have a separate overmolding, the respective overmolding is applied to the inner surface of the respective stator core in a winding region, to the winding webs and to pole slots (N) between the winding poles and several immediately adjacent electrical laminations of the adjacent stator core, arranged at its end, have no overmolding on the inner surface in the winding region to the winding web and to the pole slots between the winding poles.

2. The stator according to claim 1, wherein connectors are provided on the two end-face electrical laminations of mutually adjacent stator cores, the connectors mechanically connect between the stator cores.

3. The stator according to claim 2, wherein on one stator core, the connectors are configured as a protruding catch that extend into opposing catches that are in the form of corresponding openings suitably formed on the second stator core to produce a clamping connection.

4. The stator according to claim 1, wherein plastic lands protrude peripherally along the winding poles from the end face of one stator core, the plastic lands extend into the respective corresponding intermediate spaces of the winding poles of the adjacent stator core.

5. The stator according to claim 1, wherein two or all of the stator cores arranged axially in series have the same or approximately the same overall axial length.

6. The stator according to claim 1, wherein the slots of the stator cores are skewed or straight.

7. The stator according to claim 6, wherein in case of the skewed slots the slots ends of the slots of one stator core are aligned with the slot beginnings of the corresponding slots of the adjoining stator core, so that the continuous, skewed pole slots extend along the stator body.

8. The stator according to claim 1, wherein the respective end faces of the end laminations of the two stator cores are likewise overmolded, preferably in a thickness of approximately 0.3 mm to approximately 0.6 mm.

9. A method for producing a stator comprising the steps of: providing a first stator core formed from a plurality of stacked electrical laminations; overmolding plastic onto the first stator core; providing at least one additional stator core formed from a plurality of stacked electric laminations; overmolding plastic onto the at least one additional stator core; omitting overmolding on several immediately adjacent electrical laminations of the adjacent stator core, arranged at its end, to have no overmolding on the inner surface in the winding region to the winding web and to the pole slots between the winding poles; aligning the stator cores axially with one another; connecting the first and at least the second stator core electrically and mechanically at end-face connectors; and forming a stator body.

10. The method according to claim 9, wherein the connecting step is accomplished without tools, via a mating process or joining process.

Description

DRAWINGS

(1) The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

(2) FIG. 1 is a perspective view of two stator cores, to produce a stator body, in a preassembled state.

(3) FIG. 2 is a perspective view of a stator body composed of two stator cores.

(4) FIG. 3 is a perspective view of an alternative embodiment of two stator cores, to produce a stator body, in a preassembled state.

(5) FIG. 4 is a perspective view of the two end laminations of the stator cores of FIG. 1.

(6) FIG. 5 is a perspective view of the two end laminations of the stator cores of FIG. 3.

DETAILED DESCRIPTION

(7) In the following, the disclosure will be described in greater detail based upon the example of externally slotted stators, making reference to FIGS. 1 to 5, where like reference signs denote the same structural and/or functional features.

(8) FIGS. 1 and 3 each show a perspective view of two stator cores 10, 20, to produce a stator body 2, in a preassembled state. FIG. 2 shows a perspective view of the stator body 2 composed of the two stator cores 10, 20.

(9) The stator body 2, together with the end caps and connecting ring V, form an as yet unwound stator 1 for an electric motor. The stator 1 includes, in these embodiments, two stator cores 10, 20 arranged axially in series and resting against one another as shown in FIG. 2. Each of the stator cores 10, 20 is formed from a multiplicity of stacked electrical laminations 11, 21. In this example, the laminations 11, 21 each form winding poles 16, 26, with winding webs 17, 27 extending radially outward. The stator cores 10, 20 each include a separate overmolding U1, U2.

(10) As is clear from FIGS. 4 and 5, the respective overmolding U1, U2 is applied to the respective inner surface of the respective stator core 10, 20 in the winding region. It extends to the winding webs 17, 27 and to the end faces between the pole slots N between the winding poles 16, 26. FIG. 4 further shows a perspective view of the two end laminations (11e, 21e) of the stator cores 10, 20 from the exemplary embodiment of FIG. 1. FIG. 5 shows a perspective view of the two end laminations (11e, 21e) of stator cores 10, 20 from the exemplary embodiment of FIG. 3.

(11) The two electrical laminations 11e, 21e are located on the end faces of two stator cores 10, 20 to produce a stator 1. Corresponding connectors 19, 29 are provided to effect the mechanical connection between the stator cores 10, 20 in question.

(12) The stator cores 10, 20 are aligned axially with one another. The first and second stator cores 10, 20 are connected to one another mechanically by means of the illustrated end-face connecting elements. The configuration of the connectors 19, 29 enables this connection to be accomplished without tools. The assembly is effected exclusively via a mating connection process. The connectors 19 are configured as a protruding catch. The catch extends into the opposing catch 29, in the form of corresponding openings formed on the second stator core 20, producing a clamping connection. Advantageously, an index member 8, in the form of a recess, may be provided in the electrical laminations.

(13) In the exemplary embodiment of FIGS. 3 and 5, plastic lands 30 protrude peripherally along the winding poles 16 from the end face of one stator core 10, around the intermediate spaces of the winding poles and into the slot N.

(14) When the two stator cores 10, 20 are in the assembled state, these plastic lands 30 of the stator core 10 extend into the respective corresponding intermediate spaces of the winding poles 26 of the other stator core 20. For this purpose, several immediately adjacent electrical laminations 21, 21e of the second stator core 20, located at the end thereof, are embodied to have no overmolding U2 on the inner surface F in the winding region, winding webs 17, 27, and have no overmolding U2 on the pole slots 24 between the winding poles 26. The resulting shoulder is illustrated schematically by a circumferential line L in FIG. 5.

(15) The inner surfaces must be set back and overmolded accordingly in the indicated region of the inner surface F of the lamination. This achieves the required air gap and creepage distances. In an alternative embodiment, a configuration without this overmolding would be possible, although this would result n shorter air gap and creepage distances.

(16) The primary force holding the stator cores together is produced at a later time by the wire windings.

(17) To prevent the electrical laminations that are stacked loosely in the stator cores, from fanning out at the end faces (connecting points), the laminations are held together axially in an interlocking manner by end laminations (approximately 4 end laminations measuring approximately 2 mm). They are inserted in a set-back position in the slot region (along the winding paths), and by the resulting formation of a shoulder and the overmolding.

(18) The end laminations (e.g., the 4 mentioned end laminations), that have no axial interlocking of the overmolding, can be glued to the last overmolded electrical lamination during the overmolding process. Thus, they can be prevented from fanning out axially.

(19) As is further clear from FIG. 2, the slots N of the assembled stator cores 10, 20 are aligned. This is ensured by the fact that the slot ends 14e of the slots 14 of one stator core 10, as shown in FIGS. 4 and 5, are aligned with the slot beginnings 24a of the corresponding slots 24 of the adjoining stator core 20. Thus, continuous skewed pole slots N extending along the stator body 2 are produced in each case.

(20) In the exemplary embodiment shown in FIGS. 1 and 4, the respective end faces of the end laminations 11e, 21e of the two stator cores 10, 20 are likewise overmolded. Specifically, in a thickness of approximately 0.3 mm.

(21) The embodiment of the disclosure is not restricted to the preferred embodiment examples described above. For instance, the disclosure may also be implemented in embodiments having straight slots and in internally slotted stator bodies.

(22) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.