DE102022213148A1 - Insulating mask for a stator, stator, electrical machine and manufacturing method for a stator - Google Patents

Abstract

The invention relates to an insulating mask (10) for a stator (14), as well as a stator (14) and a method for producing a stator (14), having a plurality of individual masks (28) which can be placed axially on separable stator segments (26) of the stator (14), wherein the individual masks (28) are arranged in a circle around an imaginary stator center point (32), wherein adjacent individual masks (28) are monolithically connected to one another at connecting regions (31) by means of a connecting element (30), wherein the connecting element (30) has a separating geometry (50) at the connecting regions (31) for separating the insulating mask (10) into individual masks (28), which is designed as a notch (50) in order to reduce the material cross-section at the connecting regions (31).

Description

The invention relates to an insulating mask for a stator according to the preamble of the independent claim. The invention further relates to a stator and an electrical machine with such an insulating mask, as well as a manufacturing method for a stator with such an insulating mask.

State of the art

Increasing electrification, especially in mobile applications, is leading to a need for electrical machines with increased power density. Such machines usually use segmented stators, as this allows for smaller overall lengths and higher copper fill factors compared to solid-section stators. Segmented stators have the disadvantage that their production is significantly more complex and therefore more prone to errors, as significantly more individual parts have to be brought together and assembled. For example, according to the state of the art, two insulation masks must be provided for each segment of the stator, while a solid-section stator usually only requires a total of two insulation masks, one for each of the two axial end faces.

With the US20090229383 A1 A stator has become known that has individual tooth segments, each of which has an insulating mask placed on it. The insulating masks are manufactured separately and connected to one another in an articulated manner, so that the individual tooth segments can be bent from a ring-shaped arrangement to a linear chain in order to be able to better affect the individual teeth. However, such a manufacturing process has the disadvantage that a completely different production line has to be set up compared to the winding of so-called full-cut stators, in which the stator base body is designed as a rigid stator ring from which the stator teeth extend radially inwards.

Disclosure of the invention

Advantages of the invention

The device according to the invention and the method according to the invention with the features of the independent claims have the advantage that the insulating mask can be formed on one axial side of the stator as a one-piece, ring-shaped component, so that many individual masks can be placed on the corresponding stator segments at the same time in a single production step. However, since the individual masks are firmly connected to one another monolithically via the connecting elements, which protrude radially beyond the outer circumference of the stator segments, it is necessary to completely separate the connecting elements during the production of the stator. By forming notches in the connection area between the individual masks and the connecting elements, a clean separation surface can be created using a punching or cutting tool. This prevents remnants of the connecting elements from protruding radially beyond the outer contour of the stator segments. On the other hand, the defined separation geometry at the connection areas means that the connecting elements can be removed using a clearly defined process without there being a risk that remnants of the connecting elements will hinder the production process.

The measures listed in the dependent claims make it possible to develop advantageous further developments and improvements to the designs specified in the independent claims. It is particularly advantageous if the connecting elements are arranged - in particular completely - radially outside the individual masks, as they then do not hinder the winding process and the arrangement of the connecting wires between the stator segments. Using injection molding technology, such bow shapes of the connecting elements can be formed in a simple manner between the individual masks without having to change the tool principle. In addition, the arc-shaped connecting elements can be designed to be so elastic that different tangential distances between the individual stator segments can be set despite the completely connected connecting elements.

The notches in the connection areas are particularly advantageously designed on the radially outer circumference of the individual masks. This allows the connecting elements to be completely separated from the individual masks with a clean cut, so that no residue of the connecting elements protrudes radially beyond the outer circumference of the stator segments. This allows the wound stator to be inserted into a stator housing without hindrance.

The notches can be designed particularly advantageously as tangential notches that run along the outer circumference of the individual masks in the connection area. The tangential notches can be formed on the axially upper and/or axially lower side of the connecting elements. This makes it possible to create an optimal separation geometry for a cutting tool that acts in the axial direction.

Alternatively or additionally, notches in the axial direction can be cut out at the connection areas, which serve as axial notches on the tangential outer side and/or the tangential inner side of the arc-shaped connecting elements. This allows the material cross-section at the separation point to be further reduced, which means that the connecting element can be separated with a lower shear force.

In order to produce a smooth, flat cutting surface, the radial inner wall of the notch can be designed approximately parallel to the radial outer circumferential surface of the individual masks. The radially opposite outer wall of the notch is then angled by the notch angle to the radial outer tangential surface of the individual masks. This means that no step or punching remains after the connecting element has been sheared off.

A pointed wedge with the wedge angle is cut out at the bottom of the notch so that targeted stress peaks are generated at the desired separation point in the connection area. This directs the separation energy into the separation point in a targeted manner, which on the one hand reduces the required separation force and also increases the service life of the separation tools.

The entire insulating mask with the individual masks connected by the connecting elements can be manufactured very cost-effectively as a plastic injection-molded part. The notches can be easily formed in the plastic surface using the injection molding tool. The plastic can then be cut off at the notches using a separating or cutting tool with relatively little force.

The relatively thin design of the connecting elements with radial webs and tangential webs means that two adjacent individual masks can be moved against each other in a tangential direction without much effort. This makes it possible to widen the diameter of the stator ring after placing the one-piece mask on the ring-shaped stator segments in order to be able to wind the stator teeth better, for example by means of needle winding. The stator segments can then be joined together radially towards the stator center, whereby the connecting elements can be separated either before or after the stator segments are joined together radially.

The one-piece insulating mask for an axial side of the stator base body is made up of several individual masks for the several stator segments. A stator yoke section covers the yoke area and a stator tooth section covers the stator tooth in order to electrically insulate the winding from the stator base body. The connecting elements between two adjacent individual masks are then formed on the opposite ends of the yoke sections, in particular as radial webs that project radially outwards and are connected to one another in one piece in the circumferential direction via a further web. With such an insulating mask, the manufacture of the stator can be simplified. Because the individual masks assigned to a stator segment are connected to one another by means of the connecting elements to form a single insulating mask, only a single insulating mask needs to be put on for each end face of a segmented stator.

To electrically contact the individual tooth coils, contact elements are formed in the yoke section of the individual masks. These are preferably designed as receptacles for insulation displacement elements (IDC), which are formed in one piece with the individual masks. In particular, the winding wire can be inserted in the radial direction into these receptacles in order to be connected to the axially inserted insulation displacement elements.

A stator in which the yoke areas on their outer circumference are designed as circular arc-shaped sections and/or with a flat surface has the advantage that the outer diameter of the stator base body can be reduced in this way. In another variant, flattened areas and approximately circular areas can alternate in the circumferential direction in order to ensure that the stator segments are joined together precisely at their separation area in a stator base body manufactured using the precut technique. In the precut technique or click-cut technique, the individual sheet metal layers of ring-shaped stator lamellae are divided into individual circular segments to form the stator segments. The individual stator segments, however, remain connected to one another via predetermined breaking points by means of incomplete punching or by means of a positive connection in the tangential direction in order to be easier to transport before winding. For such a stator manufactured using the precut process, the one-piece insulating mask according to the invention is particularly suitable, since it can be placed on the stator segments as a single component and can then be spread radially with the sheet metal segments in order to wind the stator teeth.

In advantageous variants, the stator has exactly six or nine or twelve or eighteen stator segments or stator teeth, whereby in particular all individual tooth coils of the stator segments are connected to one another via a single uninterrupted winding wire. In this way, a stator with high power density can be produced with a small Installation space must be made available. For example, exactly two opposing stator segments are wound radially one after the other, so that the connecting wire between the opposing stator segments extends approximately over half the outer circumference of the stator base body.

Such a stator according to the invention is particularly suitable for use in an electrical machine that is designed as an electronically commutated motor. A rotatable rotor is mounted radially inside the wound stator, the rotor magnets of which can be set in rotation by the electronically commutated windings. For example, an electronic unit that is electrically contacted with the single-tooth coils can be arranged axially above the stator. For example, the electrical machine is designed as an EC machine with a 6/4 motor topology, with the stator having six stator teeth, each of which is arranged on a stator segment. The rotor has four poles that are formed by permanent magnets.

In the manufacturing process according to the invention, all individual masks for the individual stator segments can be placed on one axial side in one process step, since all individual masks are firmly connected to one another by means of the connecting elements to form an annular insulating mask. Due to the notches in the connection areas to the connecting elements, the latter can be separated without residue with a smooth trend surface, so that they no longer interfere when inserting the wound stator into a stator housing. The one-piece, annular insulating mask can be placed on the stator segments as long as they are in contact with one another in the tangential direction. Alternatively, the one-piece insulating mask can be designed in such a way that it can be placed on the stator segments, which are at a tangential distance from one another. It is also possible to design the connecting elements between the individual masks to be elastic in such a way that the connecting elements can follow the radial spreading and/or compression of the stator segments before they are separated from the individual masks. Depending on the manufacturing process selected, the connecting elements can be separated without leaving any residue at the notches before or after the stator segments are pressed together. In this way, the assembly effort for the insulation masks of the individual stator segments can be significantly reduced, even with a pre-cut or click-cut manufacturing process.

drawings

• 1 eine elektrische Maschine mit einem Stator mit einer erfindungsgemäßen Isoliermaske,
• 2 bis 4 verschiedene Ausführungen von Isoliermasken, anhand von Detailansichten derer Verbindungselemente.

In the drawings, embodiments according to the present invention are shown and explained in more detail in the following description. They show

• 1 an electrical machine with a stator with an insulating mask according to the invention,
• 2 to 4 different designs of insulating masks, based on detailed views of their connecting elements.

Description

1 showed a top view of an insulating mask 10 that is arranged on a stator 14 for an electrical machine 12. The stator 14 has several separable stator segments 26 - for example six - each of which has a stator tooth 24. The stator segments 26 together form an annular stator base body 34, which is reassembled in the same way using the precut technique after the individual stator segments 26 have been wound using single-tooth coils 20. The insulating mask 10 has several individual masks 28 that are connected to one another using connecting elements 30. The individual masks 28 are arranged around an imaginary stator center point 32. In the exemplary embodiment, the connecting elements 30 are in a first state and hold the individual masks 28 at a first tangential distance 36. The first tangential distance 36 of the first state is defined here by the fact that the individual stator segments 26 abut one another in the tangential direction 9 at a separating area 27, wherein these are connected to one another in particular via predetermined breaking points or form-fitting click elements to form the stator ring 34. In the exemplary embodiment of the 1 the stator segments 26 are T-shaped for example and have a yoke area 23 on the outside radially, from which the stator tooth 24 with a tooth shaft extends radially inward. Tooth feet 25 are formed on the radially inner end of the tooth shafts, which then form the magnetic poles for the rotor 13 mounted radially inside the stator 14. In 1 the individual masks 28 are arranged on the stator segments 26. In the exemplary embodiment shown, the individual masks 28 have a yoke section 40 on the radial outside, which largely covers the axial end face of the yoke region 23 of the stator segment 26, in particular at least 80% of the end face. A stator tooth section 42 extends radially inward from the yoke section 40, which largely covers the axial end face of the stator tooth 24. The stator tooth section 42 preferably also has two axial regions, which each extend along the axial direction 8 on both sides of the stator tooth 24. The stator ring 34 has in the separation areas 27 circular sections 17 with an outer diameter 46 through the imaginary stator center point 32, wherein between the separation areas 27 the stator ring 34 has flattened sections 18 in the tangential circumferential area of the stator teeth 24.

The connecting elements 30 are arranged largely outside the outer diameter 46. For example, the connecting elements 30 are U-shaped or arc-shaped. The connecting elements 30 each contact two adjacent individual masks 28 at connecting areas 31 which are formed at the tangential ends of the respective yoke sections 40. Starting from the yoke section 40 of a first individual mask 28, the connecting element 30 initially extends radially outwards and then over the first tangential distance 36 in an arc to the adjacent second individual mask 28. In the connecting areas 31, notches 50 are formed on the insulating mask 10, which allow the connecting elements 30 to be separated precisely as a defined separation geometry. The notches 50 can extend in the axial direction 8 and/or in the tangential direction 9 along the radially outer surfaces of the yoke areas 23. These notches 50 are shown in the detailed representation of the 2-4 presented in more detail.

For example, a method according to the invention for producing the stator 14 can proceed as follows. The insulating mask 10 with the interconnected individual masks 28 are placed from both axial sides onto the stator base body 34, the individual stator segments 26 of which initially lie tangentially against one another. In this case, between each stator segment 26, a connecting element 30 projects radially arcuately between the two adjacent individual masks 28 beyond the outer diameter 46. The connecting elements 30 are in a first state in which the individual masks 28 have the first tangential distance 36 from one another. The stator segments 26 are then separated and moved radially outwards so that tangential gaps 37 form between two adjacent stator segments 26. In this second state, the elastic connecting elements 30 are stretched further in the tangential direction 9, so that the two adjacent individual masks 28 are arranged with a second larger tangential distance 38, as is the case, for example, in 2 is shown. In this second state, single-tooth coils 20 can be wound onto the stator teeth 24 using a needle winding process, which are preferably connected to one another by an uninterrupted winding wire 70. In this second state, the connecting elements 30 can be cleanly severed at the notches 50 using a punching or cutting tool, such that the individual masks 28 do not protrude beyond the circumference of the yoke region 23 in the radial direction 7. To form the finished stator 14, the individual stator segments 26 are moved again in the radial direction 7 towards the stator center 32 until the yoke regions 23 again lie tangentially against one another. The stator segments 26 are preferably manufactured using precut technology, so that the tangential contour of the yoke regions 23 again engage with one another in a precisely form-fitting manner after they have been joined together. In this case, before the stator segments 26 are separated, a predetermined breaking point can be left during punching, which breaks open when separated. Alternatively, the stator segments 26 can be completely severed in the axial direction 8 and held together by means of a positive connection with respect to the tangential direction 9 before separation (click-cut technique). The individual stator segments 26 are then reconnected to form a closed stator ring 34 and pressed axially into a corresponding stator housing. Alternatively, the connecting elements 30 can also only be separated from the individual masks 28 after the stator segments 26 have been reassembled to form a closed stator ring 34. On at least one of the two axial sides of the stator 14, contact elements 21 for controlling the individual tooth coils 20 are formed on the yoke sections 40 of the individual masks 28. These can preferably be designed as axial pockets 22 for corresponding insulation displacement elements, through which the winding wire 70 is guided in the radial direction 7.

In an alternative manufacturing process, the individual stator segments 26 are first separated from the closed stator ring 34, and only then is the insulating mask 10 with the interconnected individual masks 28 placed axially on the stator segments 26. In this design, the connecting elements 30 do not have to be elastic, since they are then separated from the individual masks 28 before the stator segments 26 are reassembled radially to form a closed stator ring 34. Here, the connecting elements 30 are formed between the individual masks 28 in order to place all individual masks 28 on all stator segments 26 simultaneously in a single manufacturing step using the one-piece insulating mask 10.

In 2 is shown enlarged, just one single connecting element 30, which connects two adjacent individual masks 28 to each other. The individual masks 28 are placed axially on the stator segments 26. The individual masks 28 are here in the second state with the second tangential distance 38, which is greater than the first tangential distance 36 in the first state, in which the stator segments 26 lie tangentially against one another. In the second state, the tangential gaps 37 are formed in the tangential direction 9 between two adjacent stator segments 26, which enable the yoke sections 40 of the individual masks 28 arranged thereon to be wound onto the stator teeth 14. In this embodiment, the connecting element 30 has a longer, narrow web 52 in the tangential direction 9, which is connected to the individual masks 28 at the connecting regions 31 via two radial webs 53 running approximately in the radial direction 7. The tangential web 52 has, for example, a smaller cross-section than the radial webs 53 towards the connecting regions 31. Therefore, notches 50 are formed on the two connecting areas 31 of the two radial webs 53, which here reduce the material cross-section of the connecting webs 30 in the area of the outer diameter 46 of the stator base body 34. The notches 50 run here as tangential notches 55 both on the axially upper side 61 and on the axially lower side 62 of the connecting elements 30 in the tangential direction 9, and are preferably designed as straight grooves.

In 3 these tangential notches 55 are shown in an axial section. The upper and lower notches 50 each have a flat, axial side wall 56, which is designed as a radial inner wall 56 of the notch 50. A radial outer wall 58 is designed as a flat surface, which is arranged at a notch angle 57 to the axial inner wall 56. As a result, the notch 50 has a pointed, wedge-shaped groove base 59, which is designed as a predetermined breaking point for severing the connecting element 30. The notch angle 57 is, for example, in the range between 30° and 60°, with a notch depth 54 of the notch 50 being in the range between 5 and 20% of the maximum height 64 of the connecting element 30 in the connecting area 31.

4 shows further notches 50 in the connection area 31, which are designed here as axial notches 60, which run linearly in the axial direction 8. The axial notches 60 are formed on the outer circumference of the individual masks 28 on both sides 91, 92 of the radial webs 53 that are opposite in the tangential direction 9. The cross section of the notch 50 of the axial notches 60 corresponds in 4 approximately the cross section of the notch 50 of the tangential notches 55 according to 3 . The radial inner side 56 is again formed approximately as a flat surface in the tangential direction 9, with the radial outer wall 58 again being aligned at the notch angle 57 to the tangential inner wall 56. This again forms a pointed notch base 59, at which the connecting element 30 is sheared off in a defined manner. As in 2 As shown, the tangential notches 55 can be combined with the axial notches 60 at one end of the connecting element 30 so that the connecting element 30 can be cut off with relatively little force. 3 It can be seen that after the connecting element 30 has been sheared off at the notches 50, the insulating mask 10 no longer projects radially beyond the outer circumference 46 of the stator base body 34. In 2 and 4 the two corresponding tangential profiles 81, 82 are visible on the side surfaces of the stator segments 26, which here, for example, are tangentially joined together again after the connecting elements 30 have been separated due to the radial merging of the stator segments 26. In this case, connecting wires 70 between the individual stator segments 26 are preferably also shaped inwards in the radial direction 7 in order to enable a tangential approach of the two adjacent yoke regions 23. The connecting wires 70 are held here, for example, in guide elements 72 which are molded onto the individual masks 28. The guide elements 72 are preferably formed on the radial outside of the axial pockets 22 of the contact elements 21, preferably as grooves running in the tangential direction 9. Two adjacent stator segments 26 can be connected to one another by just a single connecting wire 70 or by means of several connecting wires 70.

It should be noted that with regard to the embodiments shown in the figures and in the description, a wide variety of combination options of the individual features are possible. For example, the specific design and arrangement of the notches 50 and the connecting elements 30 can be varied. Likewise, the specific design and the number of stator segments 26 and the individual masks 28 can be adapted to the requirements of the electrical machine 12 and its manufacturing options. The stator base body 34 can preferably be manufactured using pre-cut technology or click-cut technology, wherein the stator segments 26 are inserted exactly into their original position before punching after they have been wound. The invention is particularly suitable for use in an EC motor designed as an internal rotor, in particular for the rotary drive of components or the adjustment of parts in the motor vehicle, but is not limited to this application.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. 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

• US 20090229383 A1 [0003]

Claims (15)

Insulating mask (10) for a stator (14), comprising a plurality of individual masks (28) which can be placed axially on separable stator segments (26) of the stator (14), wherein the individual masks (28) are arranged in a circle around an imaginary stator center point (32), wherein adjacent individual masks (28) are monolithically connected to one another at connecting regions (31) by means of a connecting element (30), wherein the connecting element (30) has a separating geometry (50) at the connecting regions (31) for separating the insulating mask (10) into individual masks (28), which is designed as a notch (50) in order to reduce the material cross-section at the connecting regions (31). Isolation mask (10) after Claim 1 , characterized in that the connecting elements (30) are arc-shaped and extend from a first connecting region (30) of a first individual mask (28) radially outwards beyond the outer circumference (46) of the stator segments (26) to a second connecting region (31) on a second, adjacent individual mask (28). Insulating mask (10) according to one of the preceding claims, characterized in that the notches (50) are arranged in the radial region of the outer circumference (46) of the stator segments (26), so that in particular the individual masks (28) do not project radially outwards beyond the outer circumference (46) of the stator segments (26) at the connecting region (31) after the connecting elements (30) have been separated. Insulating mask (10) according to one of the preceding claims, characterized in that the notches (50) in the connecting region (31) run in the tangential direction (9), wherein the notches (50) are formed on an axially upper end face (61) and/or on an axial underside (62) of the connecting regions (31). Insulating mask (10) according to one of the preceding claims, characterized in that the notches (50) in the connecting region (31) run in the axial direction (8), wherein the notches (50) are formed on a tangential outer side (91) and/or on a tangential inner side (92) of the arcuate connecting elements (30). Insulating mask (10) according to one of the preceding claims, characterized in that the notch (50) has an inner wall (56) towards the stator center (32), which extends in the axial direction (8) and/or in the tangential direction (9), and has a radially opposite outer wall (58) which forms an acute notch angle (57) to the inner wall (56). Insulating mask (10) according to one of the preceding claims, characterized in that between the inner wall (56) and the radially opposite outer wall (58) the notch (50) has a pointed, wedge-shaped notch base (59), which is preferably designed as a predetermined breaking point. Insulating mask (10) according to one of the preceding claims, characterized in that the individual masks (28) and the connecting elements (30) are made monolithically from plastic - in particular as an injection-molded part - and the connecting elements (30) are designed to be separable at the notches (50) by means of a cutting tool. Insulating mask (10) according to one of the preceding claims, characterized in that the connecting elements (30) are designed to be elastically deformable, so that the connecting elements (30) can be deformed from a first state with a predetermined first tangential distance (36) between the individual masks (28) into a second state with a second tangential distance (38) between the individual masks (28), which is greater than the first distance (36). Insulating mask (10) according to one of the preceding claims, characterized in that the individual masks (28) each have a stator tooth section (42) and a yoke section (40) formed radially outward thereon, which are designed to cover the stator segment (26), and that the connecting regions (31) with the connecting elements (30) formed thereon are each formed on two mutually opposite tangential sides of the respective yoke sections (40). Insulating mask (10) according to one of the preceding claims, characterized in that at least one individual mask (28) has a contact element (21) for electrically contacting an electrical winding (20), which is designed in particular as an axial pocket (22) for an insulation displacement connection. Stator (14) with at least one insulating mask (10) according to one of the Claims 1 until 11 , characterized in that the stator (14) is composed of several stator segments (26) which are produced in particular by means of a click-cut process or precut process, wherein yoke regions (23) of the stator segments (26) have circular arc-shaped sections (17) on their outer circumference (46) at the connecting regions (31) and flat circumferential sections (18) tangentially therebetween, and preferably the stator segments (26) are composed of individual axially stacked sheet metal laminations (16). Electric machine (12) with a stator (14) according to one of the Claims 12 , characterized in that a rotor (13) having permanent magnets is rotatably mounted radially within the stator (14) - and in particular the stator (14) is electronically commutable by means of an electronic unit. Method for producing a stator (14) from a plurality of separate stator segments (26), each having a yoke region (23), from which a stator tooth (24) extends radially inward, characterized by the following steps: - providing an insulating mask (10), in particular an insulating mask (10) according to one of the Claims 1 - 11 , comprising a plurality of individual masks (28) which are arranged around an imaginary stator center point (32) and adjacent individual masks (28) are connected to one another by means of at least one connecting element (30), - arranging the stator segments (26) with a tangential winding distance (38) between adjacent yoke sections (40) - axially placing the insulating mask (10) with the individual masks (28) on the correspondingly arranged stator segments (26) - winding the stator teeth (24) by means of needle winding with individual tooth coils (20), in particular by means of a single uninterrupted winding wire (70) - severing the connecting elements (30) at the notches (50) - radially compressing the stator segments (26) to a final distance (36), in particular until the yoke regions (23) of the stator segments (26) touch tangentially, - mechanically connecting the individual Stator segments (26). Method for producing a stator (14), wherein the insulating mask (10) with the individual masks (28) is placed on a stator base body (34) - produced by means of pre-cut technology or click-cut technology - in which individual stator segments (26) are arranged in a closed stator ring (34), and then the stator ring (34) is separated into individual stator segments (26), wherein the individual stator segments (26) are radially expanded together with the connecting elements (30) between the individual individual masks (28) in order to wind the isolated stator teeth (24) - and in particular subsequently the individual masks (28) are separated by separating the connecting elements (30) in order to reassemble the stator segments (26) radially to form a stator ring (34).

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