Stator, method for producing stator segments, method for producing a stator

Abstract

Stator for an electric motor, wherein the stator is divided into at least two stator segments in the circumferential direction, wherein an electrical insulating layer is provided on the surface of the stator segment, wherein an end cap is provided at each of the axial end regions of the stator segment, wherein each stator segment carries a winding and / or is provided with a winding, characterized in that the respective stator segment, the respective insulating layer and the respective end caps are designed as a composite part, wherein the respective end cap is designed as a plastic injection-molded part directly cast onto the respective stator segment, wherein the respective end cap (3) has a respective cheek which has a respective locking groove (9), wherein a retaining ring is pushed axially from the axial direction, which holds the respective segments together in a ring shape and thus connects them, wherein a respective locking lug on the retaining ring, which hooks into the respective locking groove (9), prevents the retaining ring from slipping off.

Description

The invention relates to a stator, a method for producing stator segments and a method for producing a stator.The stator of an electric machine usually consists of a stack of thin and insulated dynamo sheets which are assembled to form a compact stator core. The thin sheets reduce eddy currents occurring in the iron and reduce losses caused thereby.Various methods are known for joining the individual sheets. Welding the sheets, like die-packing, leads to short circuits between the individual sheets, whereby the eddy current losses are greatly increased.DE 10 64 617 B discloses a method for producing a stator core, in which the individual dynamo lamination sections are adhesively bonded together. However, the method is time consuming and expensive.DE 198 57 954 A1 discloses an electronically commutated direct current motor, the stator of which is composed of circular ring segments.DE 199 61 339 A1 discloses an electric machine in which single-tooth winding is implemented.A stator arrangement is known from US 2004 / 0 034 988 A1 and DE 10 2005 051 506 A1, wherein the stator is likewise composed of individual segments.The object of the invention is therefore to construct the stator core in a cost-effective and simple manner from sections of dynamo sheets.According to the invention, the object is achieved in the stator according to claim 1, in the method for producing stator segments according to the features specified in claim 9 or 10 and in the method for producing a stator according to the features specified in claim 11.Important features of the invention in the stator for an electric motor are that the stator is divided in the circumferential direction into at least two segments, that each stator segment consists of a stack of iron sheets, that an electrical insulating layer is provided on the stator segment, that a respective end cap is provided at the ends of the stator segment, that the stator segment is provided with a winding, that the stator segment, the insulating layer and the end caps are designed as a composite part.It is advantageous here that a compact stator segment can be produced in a simple manner, which is integral, which is simple to handle, and the individual plates of which are completely electrically insulated.In an advantageous embodiment, the stator has a phase separator between the individual stator segments on the winding of each stator segment. It is advantageous here that, with a small overall size, voltage breakdowns between the windings of adjacent stator segments are prevented within the scope of the usual use of the stator.In a further advantageous embodiment, the stator has an insulating layer as a plastic injection-molded part cast directly onto the stator segment. In a further advantageous embodiment, any desired electrically insulating material is used instead of plastic. It is advantageous here that the insulating layer can be attached to the laminated core directly, i.e. positively, in a configuration according to requirements, i.e. as a plastic with low electrical conductivity.In a further advantageous embodiment, the stator has end caps which are designed as a plastic injection-molded part cast directly onto the stator segment. In a further advantageous embodiment, any desired electrically insulating material is used instead of plastic. It is advantageous here that the end caps with different functional regions, such as guiding of the winding wire, depositing possibilities for wire ends or the like, made of plastic with low electrical conductivity, can be attached directly to the axial ends of the laminated core.In a further advantageous embodiment, the stator has the insulating layer and the end caps in one piece as a plastic injection-molded part cast directly onto the stator segment.In an advantageous embodiment, any desired electrically insulating material is used instead of plastic. It is advantageous here that the insulating layer and the end caps made of plastic with low electrical conductivity can be attached directly to the laminated core. A further advantage is that the one-piece plastic part enables an improvement in the connection of the individual sheets.In a further advantageous embodiment, a phase separator is connected in a positive-locking manner to the insulating layer in the stator segment. It is advantageous here that, when applying the insulating layer, the phase separator can be fixed in its position.In a further advantageous embodiment, in the stator segment, the phase separator is embodied integrally with the insulating layer. It is advantageous here that the insulating layer and the phase separator are manufactured from a single material which can be attached in a single working step.In a further advantageous embodiment, recesses present in the iron plates in the stator segment are filled by plastic. In a further advantageous embodiment, any desired electrically insulating material is used instead of plastic. It is advantageous in this case that axially running webs can thereby be produced along the normal direction of the segments, which connect the two end caps to one another. This makes it possible to achieve a further reinforcement of the connection of the individual sheets.Important features of the invention in the method for producing stator segments are that, in a first step, iron laminations of a certain number are loosely stacked, in a second step, an insulating layer and end caps are injection-molded from a plastic onto the two ends of the iron lamination stack, and in a third step, a winding is wound onto the stator segment.It is advantageous here that the iron sheets are not connected in a materially integral manner, which would be achieved, for example, by welding or punching, but rather are designed as a composite part. A further advantage in this case is that a compact unit is created which is easy to handle.In an advantageous embodiment of the method, a phase separator is placed in the winding region on the stack of iron sheets before the insulating layer is injected. It is advantageous here that, when the iron sheets are inserted into the injection mold, the phase separator is inserted at the location provided for it. The insulating layer of plastic fixes the phase separator at this location. After winding the stator segment, the phase separator is placed over the winding.In an advantageous embodiment, the magnetic ring for the stator is composed of the stator segments according to the invention.Further advantages are evident from the dependent claims. The invention is not limited to the combination of features of the claims. The skilled person will be familiar with further meaningful combination possibilities of claims and / or individual claim features and / or features of the description and / or of the figures, in particular from the task and / or the task which arises by comparison with the prior art.The invention will now be explained in more detail with reference to the drawings:FIG. 1 shows a sectional view of a stator segment according to the invention.FIG. 2 shows this stator segment according to the invention in an oblique view.FIG. 3 shows a sectional view of a further embodiment of the stator segment according to the invention.In FIGS. 4 aand 4 b, this further embodiment is shown in two oblique views, wherein FIG. 4 aspecifies the yoke of the stator segment, while FIG. 4 bshows an oblique view rotated by approximately 180°.FIGS. 1 and 2 show a first exemplary embodiment of the connection according to the invention of the iron sheets.FIG. 1 shows the section of a stator lamination designed as an iron lamination 1, as is used for the construction of a single segment for a segmented stator. The annular stator can be divided into individual segments, with a division into individual poles being possible, each consisting of a tooth 13 and a connecting yoke 12. The iron laminations 1 are stacked one on top of the other in a certain number until the desired length of the stator segment 2 is reached. This laminated core is to be connected in the manner according to the invention, so that a stable unit is created for the further machining.The stack of individual iron sheets 1 must be insulated from the copper winding which is wound onto the tooth 12 and is not shown in FIG. 1. This insulation consists of an insulating paper, which is shown in the figure as phase separator 5, and insulating layer 4, which consists of plastic. The plastic layer is applied directly to the stator segment by the injection molding process. For this purpose, the loosely stacked iron sheets 1 are placed in an injection mold, the phase separator 5 is placed on the yoke 12 of the stator segment 2 as shown in FIG. 1, and the entire region of the tooth 13 is sheathed with the insulating plastic.After winding the stator segment 2, the phase separator 5 is placed over the winding. The windings of adjacent segments are thus insulated from one another by two layers of the phase separator 5.FIG. 2 shows an oblique view of the stator segment 2 shown in FIG. 1, the yoke 12 being not enveloped by the insulating layer. The winding region 10 of the tooth 13 is completely sheathed by the insulating layer 4. The phase separator 5 is not shown in this figure.The end region of the stator segment, which is illustrated in FIG. 2, is closed off by a special end cap 3. This end cap 3 is integrally cast together with the insulating layer onto the stator segment 2.The end cap 3 consists of the two cheeks 11 which prevent lateral slipping of the winding wire in the winding region 10. The cheek 11 located on the side of the yoke 12 comprises a latching groove 9 and an eyelet 8, the latching groove 9 being required when the stator segments 2 are assembled to form a closed ring. For this purpose, a retaining ring coming from the axial direction is pushed axially on, which holds the individual segments together in the form of a ring shape and thus connects them. A latching lug on the retaining ring, which hooks into the latching groove 9, prevents the retaining ring from slipping off. The retaining ring and the latching lug located thereon are not shown in the figure for better clarity. A cable tie can be fastened to the eyelet 8, with which the winding wire ends are fastened to the stator.FIGS. 3 and 4 show a further exemplary embodiment in which the stack of iron sheets is connected by webs 7.FIG. 3 shows the section of an iron sheet 1 according to the invention, which has a groove 6 in the region of the yoke 12. At the lower end of the tooth 13 a groove 6 is also cut out. A web 7 made of plastic is injected into each of the two grooves 6. The phase separator 5 is designed to integrate the function of the insulating layer 4 shown in FIG. 1. This phase separator 5 can be designed, for example, as insulating paper which is folded according to the shape of the iron sheet and is inserted into the winding region 10.FIG. 4 ashows an oblique view of the stator segment 2, wherein the yoke 12 can be seen in the upper region and the tooth 13 can be seen in the lower region. In the front area of the figure, the end cap 3 is shown.As in the first variant, the loosely stacked iron sheets 1 are placed in an injection mold. Subsequently, the insulating paper, which is used as phase separator 5 in this embodiment, is inserted at winding region 10 of tooth 13, and end cap 3 and web 7 are injection molded directly onto stator segment 2 from plastic.In FIG. 4 b, which shows the stator segment 2 rotated axially by approximately 180°, the second web 7 can be seen. The two webs 7 connect the two end caps 3 to one another. In this way, the laminated iron sheets 1 are held in the desired shape and, in conjunction with the end caps 3, form the stator segment 2 which can now be wound.The details of the end cap 3 such as cheeks 11, eyelet 8 and latching groove 9 fulfil the same purposes in this embodiment as already described in FIGS. 1 and 2.List of reference characters1 Iron plate 2 Stator segment 3 End cap 4 Insulating layer 5 Phase separator 6 Groove 7 Web 8 Eyelet 9 Latching groove 10 Winding region 11 Cheek 12 Yoke 13 Tooth

Claims

Stator for an electric motor, wherein the stator is divided in the circumferential direction into at least two stator segments, wherein an electrical insulating layer is provided on the surface of the stator segment, wherein in each case one end cap is provided at the axial end regions of the stator segment, wherein each stator segment carries a winding and / or is provided with a winding, characterized in that the respective stator segment, the respective insulating layer and the respective end caps are designed as a composite part, wherein the respective end cap is designed as a plastic injection-moulded part which is cast directly onto the respective stator segment, wherein the respective end cap (3) has a respective cheek which has a respective latching groove (9), wherein a retaining ring, which comes from the axial direction and holds the respective segments together as a ring shape and thus connects them, is pushed axially on, wherein a respective latching lug on the retaining ring, which catches in the respective latching groove (9), is designed to engage with one another, The retaining ring is prevented from slipping off.A stator according to claim 1, characterized in that each stator segment comprises a stack of iron sheet pieces.Stator according to at least one of the preceding claims, characterized in that a phase separator, in particular insulating paper, is provided between the individual stator segments on the winding of each stator segment.Stator according to at least one of the preceding claims, characterized in that the insulating layer is designed as a plastic injection-moulded part which is cast directly onto the stator segment.Stator according to at least one of the preceding claims, characterized in that the insulating layer and the end cap are formed in one piece.Stator according to at least one of the preceding claims, characterized in that the phase separator is connected to the insulating layer in a form-fitting manner.Stator according to at least one of the preceding claims, characterized in that the phase separator is formed integrally with the insulating layer.Stator according to at least one of the preceding claims, characterized in that recesses present in the iron sheet pieces are filled by the plastic, in particular for forming axially running webs which serve for connecting the end caps lying axially opposite, in particular a one-piece connection.Method for producing stator segments according to one of the preceding claims, characterized in that in a first step iron laminations of a specific number are loosely stacked, in a second step an insulating layer and end caps are injection-moulded from a plastic onto the two ends of the iron lamination stack, in a third step a winding is wound onto the stator segment.Method for producing stator segments according to Claim 9, characterized in that, before the injection moulding of the insulating layer, a phase separator is placed in the winding region on the stack of iron sheets.Method for manufacturing a stator according to claim 9 or 10, characterised in that the stator or the magnetic ring is assembled from stator segments.

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