WO2021219158A1

WO2021219158A1 - Assembly of a stator

Info

Publication number: WO2021219158A1
Application number: PCT/DE2021/100308
Authority: WO
Inventors: Christian Gilde
Original assignee: Schaeffler Technologies AG & Co. KG
Priority date: 2020-04-30
Filing date: 2021-03-29
Publication date: 2021-11-04
Also published as: DE102020111769A1

Abstract

The invention relates to the assembly of a stator (10), wherein a stator yoke (1) is pushed over stator teeth (3) which have stator windings (5), and a connection section (4) of each stator tooth (3) is received in a respective recess (2) of the stator yoke (1). After the pushing process, the stator teeth (3) are initially not fixed to the stator yoke (1). Each connection section (4) is clamped in the corresponding recess (2) by a force (210) oriented radially inwards. Each recess (2) and each connection section (4) has at least one respective diagonal surface (21, 22, 41, 42) which is structured such that the clamping of each connection section (4) in the respective recess (2) is improved.

Description

ASSEMBLING A STATOR

The invention relates to the assembly of a stator by joining stator yoke and stator teeth, as well as a stator and an electric motor.

When assembling stators, it is known to join the stator yoke and stator teeth axially. The stator yoke is pushed in the axial direction over the stator teeth, which already carry the stator windings. Since the stator teeth are also fixed on the stator yoke by joining, the forces ultimately responsible for fixing the stator teeth on the stator yoke themselves cause high joining forces during joining. These required high joining forces mean that stators are often joined in segments, i.e. the stator yoke is initially not a whole element, e.g. a complete closed ring, but is divided into several segments, which are separated by the stator teeth that are assigned to the respective segment. be pushed. Since there are obviously fewer stator teeth on a segment of the stator yoke than on the entire stator yoke, this reduces the required joining forces. However, this increases the number of joining processes and then the individual segments of the stator yoke still have to be connected to one another.

The object of the invention is therefore to provide a method for assembling stators in which the number of stator teeth to be joined at the same time is not limited by the required joining forces.

The object is achieved by a method according to claim 1. Claim 9 relates to a corresponding stator and claim 10 to a corresponding electric motor. Subclaims relate to advantageous developments.

The method for assembling a stator comprises at least the following steps: First, stator windings are applied to stator teeth. Each stator tooth has a connecting section with at least one inclined surface. Then a stator yoke with a large number of recesses is pushed onto the stator teeth. This is done by moving the stator teeth and stator yoke relative to one another in an axial direction; each recess accommodates a connecting section of a respective stator tooth. Each recess points each have at least one inclined surface; each such inclined surface of a recess is spaced apart from each inclined surface of the at least one inclined surface of the connecting section which the respective recess receives.

A force is then exerted on each stator tooth in a radial inward direction. As a result, each of the at least one inclined surface of the connecting section of the respective stator tooth is brought into contact with one of the at least one inclined surface of the respective recess. In this way, a jamming between the stator tooth and stator yoke is to be achieved. With materials commonly used for stator teeth and stator yoke (such as steel), the friction between the inclined surfaces of the recess and the connecting section is relatively low; if the jamming is to take place by self-locking, this requires relatively small angles on the inclined surfaces. This in turn leads to a higher, often too high, space requirement in the radial direction for the displacement of the stator teeth until they are jammed; because there must also be space inside the stator for a rotor and the associated air gap. Therefore, according to the method, each of the inclined surfaces of the recess and the connecting section is structured in such a way that the jamming of the respective connecting section in the respective recess is improved; As a result, larger angles are possible on the inclined surfaces, which reduces the space required in the radial direction for the stator teeth.

Since the inclined surfaces of the connecting section and the recess are still spaced from one another while the stator yoke is being pushed onto the stator teeth, no joining forces occur during this pushing-on, regardless of how many recesses and stator teeth are involved. The stator teeth are only fixed on the stator yoke in a further step by exerting the radial forces on each stator tooth, as a result of which the connecting section of the respective stator tooth is fixed in the corresponding recess. The structuring of the inclined surfaces of the connecting section and the recess enables larger angles on the inclined surfaces and thus less space requirement in the radial direction, without weakening the fixation of the stator teeth on the stator yoke to an inadmissible extent. The axial direction here is the direction of an axis of rotation about which, in the case of an electric motor in which the stator is used, a corresponding rotor of the electric motor rotates when the electric motor is in operation. Said radial direction for each stator tooth is perpendicular to the axial direction defined above. The direction radially inwards means, again with reference to a complete electric motor, perpendicularly in the direction of the above-mentioned axis of rotation.

In particular, each connecting section can have two mutually opposite inclined surfaces, and accordingly each recess then has two mutually opposite inclined surfaces.

In one embodiment, the stator yoke and stator teeth are each composed of a large number of individual metal sheets; the individual sheets are electrically isolated from one another. The structuring of the inclined surfaces results in this embodiment from the fact that each sheet metal of the stator yoke in the area of the recesses and each sheet metal of a stator tooth in the area of the connecting section has a contact surface which is inclined to a perpendicular to the sheet metal plane. When the respective force is exerted on each stator tooth in the inward radial direction, the contact surfaces of the laminations of the stator yoke come into contact with the contact surfaces of the laminations of the respective stator tooth. The contact surfaces on the metal sheets of the stator teeth and stator yoke represent additional surfaces for friction and pressure, as a result of which the jamming of a connecting section in a corresponding recess is improved.

In a further development, the metal sheets for the stator yoke and stator teeth are formed by punching. The contact surfaces of the metal sheets for the stator yoke and the contact surfaces of the metal sheets for the stator teeth are formed during the punching process. In this way, the contact surfaces and thus ultimately the structuring of the inclined surfaces of connecting sections and recesses can be produced in an efficient manner. When separating sheet metal by punching, an edge is created on the sheet metal. At this edge there is a smooth area that extends in the direction of the movement of the punching tool into the material, i.e. perpendicular to the sheet metal surface in this case. And there is an area on this edge where the material breaks out of the vertical direction. The latter area can be used as a Contact surface in the above sense can be used for the respective punched sheet. The metal sheets must be arranged in such a way that the contact surfaces can come into contact as explained above. The contact surfaces produced in this way also contribute to electrical insulation of the individual sheets from one another, which has the effect of reducing the eddy currents that occur when the stator is operated in an electric motor. In a particularly efficient embodiment, the sheets for the stator yoke and stator teeth are punched from common starting sheets. The punched-out metal sheets are stacked for the stator yoke and stator teeth while maintaining their relative orientation and are connected to one another accordingly. Maintaining the relative orientation here means that two sheet metal surfaces that point in a defined common direction during punching also point in a defined common direction when the individual sheets are stacked, which, however, can differ from the common direction during punching. Before the stator yoke is pushed onto the stator teeth, the stator teeth are rotated through 180 ° about a respective central axis running in the radial direction. In this way, the contact surfaces of the metal sheets formed during punching come into the correct position with respect to one another in order to come into contact with one another when the radial force is exerted on the stator teeth.

In general, the stator teeth can also be secured on the stator yoke by sprinkling them.

In a general development, a wedge is introduced between a surface of a connecting section of a stator tooth and a wall area of a recess of the stator yoke in which the connecting section is received in order to effect an additional fixation of the stator tooth on the stator yoke. The surface of the connecting section just mentioned is different from each of the at least one inclined surface of the connecting section.

In an alternative development, an area between a surface of a connecting section of a stator tooth and a wall area of a recess of the stator yoke, in which the connecting section is received, is injected with a plastic in order to effect an additional fixation of the stator tooth on the stator yoke. The surface of the connecting portion just mentioned is different from each of the at least one inclined surface of the connecting portion. Instead of spraying the area with plastic, the area can also be filled with trickling resin.

It is also conceivable to combine the two aforementioned developments, i.e. to use a wedge and inject the remaining area between the surface of a connecting section of a stator tooth and the wall area of a recess of the stator yoke with plastic or fill it with trickling resin.

In one embodiment, the stator yoke as a whole is pushed over all of the stator teeth of the stator at the same time. This means that the stator yoke is not segmented in this embodiment; only a single joining process is therefore required for the stator.

A stator comprises a stator yoke and a plurality of stator teeth which carry stator windings of the stator. Each stator tooth has a connecting section with at least one inclined surface, which is received in a respective recess of the stator yoke of the stator that has at least one inclined surface. Each of the inclined surfaces of the recess and connecting section is structured in such a way that clamping of the respective connecting section in the respective recess is improved. Such a stator can in particular be produced in a simple manner using the method described above.

An electric motor has a stator described above. Since the stator, as said, can be manufactured in a simple manner, the lowering position of the electric motor is also simplified overall.

In the following, the invention and its advantages are explained in more detail at Fland of the accompanying drawings.

FIG. 1 schematically shows a situation before the stator yoke and stator teeth are joined.

FIG. 2 schematically shows a situation after the stator yoke and stator teeth have been joined. FIG. 3 schematically shows a situation in which the stator teeth are jammed with the stator yoke.

FIG. 4 schematically shows a view of a recess in the stator yoke and of a connecting section of a stator tooth. FIG. 5 shows schematically sections from laminated cores for the stator tooth and stator yoke, in the situation of FIG. 2.

FIG. 6 shows schematically sections from laminated cores for the stator tooth and stator yoke, in the situation of FIG. 3.

FIG. 7 schematically shows a further situation in which the stator teeth are jammed with the stator yoke.

FIG. 8 schematically shows a further situation in which the stator teeth are jammed with the stator yoke.

Figure 9 shows schematically an electric motor.

The drawings relate only to exemplary embodiments of the invention and should therefore in no way be interpreted as a restriction of the invention to the exemplary embodiments shown.

1 shows a situation before joining a stator yoke 1, of which only a section is shown here, with stator teeth 3. Stator windings 5 are wound around the stator teeth 3. The stator yoke 1 has cutouts 2. In this exemplary embodiment, each recess 2 has two inclined surfaces 21 and 22. Each stator tooth 3 has a connecting section 4, and each connecting section 4 has two inclined surfaces 41 and 42. The inclined surface 21 is intended to come into contact with the inclined surface 41. The inclined surface 22 is provided to come into contact with the inclined surface 42. The stator yoke 1 and stator teeth 3 are joined in an axial direction, which here is perpendicular to the plane of the drawing.

2 shows a situation after the stator yoke 1 and stator teeth 3 have been joined in the axial direction perpendicular to the plane of the drawing. Each connecting section 4 is pushed into a corresponding recess 2. The inclined surfaces 21, 22 of the recesses 2 are spaced apart from the corresponding inclined surfaces 41, 42 of the connecting sections 4. Since this spacing also exists during the joining, that is to say the insertion of the connecting sections 4 into the recesses 2, the joining takes place without joining forces. The stator windings 5 on the stator teeth 3 are pushed into the stator yoke 1 with the stator teeth 3.

Next, a force 210 is applied to each of the stator teeth 3 in an inward radial direction 200. This leads to the situation shown in FIG. 3.

FIG. 3 shows a situation in which the stator teeth 3 are jammed with the stator yoke 1 as a result of the exertion of the force 210 (see FIG. 2). As before, each connecting section 4 is located in a corresponding recess 2. Here, however, the inclined surface 21 is in contact with the inclined surface 41, and the inclined surface 22 is in contact with the inclined surface 42. It can be seen that through the use of inclined surfaces , in particular two corresponding inclined surfaces 41, 42, 21, 22 at connecting section 4 and recess 2, the jamming between stator yoke 1 and stator teeth 3 can be achieved simply by force 210 inward in radial direction 200. Since, during operation of an electric motor in which the stator shown here is being assembled, essential forces on the stator teeth 3 are also directed in the radial direction 200 inwards or tangentially to the air gap of the electric motor, but not in the opposite direction to the radial direction 200, ie not radially outwards, the jamming between stator yoke 1 and stator teeth 3 is ensured in a simple manner during operation of the electric motor.

Fig. 4 shows a detail of a stator tooth 3 with a connecting section 4, which is received in a recess 2 in the stator yoke 1 and clamped there. The representation therefore corresponds to the situation in FIG. 3; the inclined surface 21 is in contact with the inclined surface 41, and the inclined surface 22 is in contact with the inclined surface 42 , enclose an angle 31; This applies analogously to the inclined surfaces 21 and 41. If the connection section 4 is to be jammed in recess 2 by self-locking, the maximum permissible angle 31 is smaller, the lower the friction between the Inclined surfaces 22 and 42, or the inclined surfaces 21 and 41 is. However, the smaller the angle 31, the greater the space requirement of the stator teeth 3 in the radial direction 200 for displacement by the respective force 210 (see FIG To keep within the permissible tolerances, it is advantageous to choose a larger angle 31. However, so that the fixation of the connecting section 4 in the recess 2 and thus the stator tooth 3 on the stator yoke 1 is not unduly weakened, the inclined surfaces 21, 22, 41, 42 are structured in such a way that the jamming of the connecting section 4 in the recess 2 is improved . A possible structuring of the inclined surfaces 21, 22, 41, 42 is explained with reference to FIGS. 5 and 6.

FIG. 5 shows details from a connecting section 4 and the stator yoke 1.

The situation shown corresponds to the situation shown in Fig. 2, i.e. the connecting section 4 is received in a recess 2 (see Fig. 2) of the stator yoke 1, but the inclined surfaces 42 and 22 are spaced from one another.

Here, the structuring of the inclined surfaces 22 and 42 is shown, by means of which a jamming of the connecting section 4 in the recess 2 is to be improved. In the embodiment shown, the stator tooth 3 (see FIG. 2) and thus the connecting section 4 consists of a stack of metal sheets 9 which are electrically insulated from one another. The stator yoke 1 also consists of a stack of metal sheets 8 which are electrically insulated from one another. The sheets 8 and 9 are formed by punching and therefore have an edge 81 and 91, respectively, produced by the punching tool. At the edge 81 there is a smooth area 82 which is oriented perpendicular to a plane 85 of the sheet 8 and thus parallel to a perpendicular 80 to the sheet plane 85, and an area which arises when the material of the sheet 8 breaks out during punching; The latter area here forms the contact surface 83, which is inclined relative to the perpendicular 80. Analogously, there is a smooth area 92 at the edge 91, which is oriented perpendicular to a plane 95 of the sheet 9 and thus parallel to a perpendicular 90 to the sheet plane 95, and an area that arises when the material of the sheet 9 breaks out during punching ; The latter area here forms the contact surface 93, which is against the perpendicular 90 is inclined. The perpendiculars 80 and 90 in FIG. 2 would each be perpendicular to the plane of the drawing.

The required positioning of the contact surfaces 83 and 93 shown here can be easily achieved, for example, if the sheets 8 for the stator yoke 1 and the sheets 9 for the stator tooth, to which the connecting section 4 shown belongs, are punched from common starting sheets and then while maintaining their relative Orientation each for the stator tooth and the stator yoke 1 are stacked. After this stacking, the perpendiculars 80 and 90 shown antiparallel in FIG. 5 would initially be parallel to one another. Then the stator tooth is rotated by 180 degrees about a central axis 30 running in radial direction 200 (see FIG. 4) before the stator yoke 1 is pushed over the stator teeth. This leads to the shown position of the contact surfaces 83 and 93 with respect to one another.

FIG. 6 is an illustration corresponding to the illustration in FIG. 5, in which the elements shown have already been explained. However, the situation shown corresponds to that shown in Fig. 3, i.e. the inclined surfaces 22 and 42 have been brought into contact with one another by a force in a radial inward direction. This also results in contact between the contact surfaces 83 and 93, and thus additional friction and pressure. This improves the jamming of the stator tooth 3 in the recess 2.

FIG. 7 shows a situation analogous to the situation shown in FIG. 3; accordingly, most of the elements shown have already been explained for FIG. 3. In the situation shown in FIG. 7, too, the stator teeth 3 are jammed with the stator yoke 1; the inclined surface 21 is in contact with the inclined surface 41, and the inclined surface 22 is in contact with the inclined surface 42. In addition, a wedge 6 is inserted into each recess 2. The wedge 6 is in contact with a surface 43 of the corresponding connecting section 4, which is different from the inclined surfaces 41, 42 of the respective connecting section 4. Likewise, each wedge 6 is in contact with a wall area 23 of the respective recess 2; the wall area 23 is different from each of the inclined surfaces 21, 22 of the respective recess 2. The wedge 6 represents an additional securing of the respective stator tooth 3 in its respective position, so it also makes it more difficult to unintentionally release the jamming between stator tooth 3 and stator yoke 1. FIG. 8 shows a situation analogous to the situation shown in FIG. 3; accordingly, most of the elements shown have already been explained for FIG. 3. In the situation shown in FIG. 8, too, the stator teeth 3 are jammed with the stator yoke 1; the inclined surface 21 is in contact with the inclined surface 41, and the inclined surface 22 is in contact with the inclined surface 42. The surface 43 is different from the inclined surfaces 41, 42 of the respective connecting section 4; the wall area 23 is different from each of the inclined surfaces 21, 22 of the respective recess 2. The plastic 45 in each case represents an additional securing of the respective stator tooth 3 in its respective position, so it also makes it more difficult to inadvertently release the jamming between stator tooth 3 and stator yoke 1.

9 shows an electric motor 300 with a stator 10 and a rotor 50 with a rotor shaft 51. An axis of rotation 110 is also shown, around which the rotor 50 of the

Electric motor 300 rotates during operation of the electric motor 300. The direction of this axis of rotation 110 is the axial direction 100 in the context of this application.

List of reference symbols

1 stator yoke 2 recess

3 stator tooth

4 connecting section

5 stator winding

6 wedge 8 sheet

9 sheet

10 stator

21 bevel

22 inclined surface 23 wall section

30 central axis

31 angles

41 bevel

42 sloping surface 43 surface

44 area

45 plastic

50 rotor

51 rotor shaft 80 vertical (to the plane of the sheet)

81 sheet edge

82 smooth area

83 contact surface

85 sheet plane 90 perpendicular (to sheet plane)

91 sheet edge

92 smooth area 93 contact surface 95 sheet metal plane 100 axial direction 110 rotation axis 200 radial direction

210 power 300 electric motor

Claims

1. A method for assembling a stator (10), comprising at least the following steps:

Applying stator windings (5) to stator teeth (3), each stator tooth (3) having a connecting section (4) with at least one inclined surface (41, 42);

Sliding a stator yoke (1) with a plurality of recesses (2) onto the stator teeth (3) in an axial direction (100), each recess (2) receiving a connecting section (4) of a respective stator tooth (3), each recess ( 2) each has at least one inclined surface (21, 22), and each such inclined surface (21, 22) of a recess (2) of each inclined surface (41, 42) of the at least one inclined surface (41, 42) of the connecting section (4), which the respective recess (2) receives, is spaced apart;

Exerting a force (210) on each stator tooth (3) in a radial direction (200) inward, through which force (210) each of the at least one inclined surface (41, 42) of the connecting section (4) of the respective stator tooth (3) is brought into contact with one of the at least one inclined surface (21, 22) of the respective recess (2), each of the inclined surfaces (21, 22, 41, 42) of recess (2) and connecting section (4) being structured in such a way that a jamming of the respective connecting section (4) in the respective recess (2) is improved.

2. The method according to claim 1, wherein the stator yoke (1) and stator teeth (3) are composed of a plurality of individual sheets (8, 9), each sheet (8) of the stator yoke (1) in the region of the recesses (2) and each sheet (9) of a stator tooth (3) in the area of the connecting section (4) has a contact surface (83, 93) which is inclined to a perpendicular (80, 90) to the sheet metal plane (85, 95), and when exercising the one Force (210) on each stator tooth (3) in the radial direction (200) inwards the contact surfaces (83) of the metal sheets (8) of the stator yoke (1) come into contact with the contact surfaces (93) of the metal sheets (9) of the respective stator tooth (3).

3. The method according to claim 2, wherein the sheets (8, 9) for the stator yoke (1) and stator teeth (3) are formed by punching, and the contact surfaces (83) of the sheets (8) for the stator yoke (1) and the contact surfaces ( 93) of the metal sheets (9) for the stator teeth (3) are formed during the punching process.

4. The method according to claim 3, wherein the sheets (8, 9) for stator yoke (1) and stator teeth (3) are punched from common starting sheets, the punched sheets (8, 9) while maintaining their relative orientation each for stator yoke (1) and stator teeth (3) are stacked and connected to one another, and the stator teeth (3) are rotated by 180 ° about a respective central axis (30) extending in the radial direction (200) before the stator yoke (1) is slid on.

5. The method according to any one of the preceding claims, wherein the stator teeth (3) are additionally secured by a droplet.

6 The method according to any one of the preceding claims, wherein between a surface (43) of a connecting section (4) of a stator tooth (3) and a wall area (23) of a recess (2) of the stator yoke (1) into which the connecting section (4) is received is, a wedge (6) is introduced.

7. The method according to any one of the preceding claims, wherein an area (44) between a surface (43) of a connecting section (4) of a stator tooth (3) and a wall area (23) of a recess (2) of the stator yoke (1), in which the connecting section (4) is received, is injected with a plastic (45).

8. The method according to any one of the preceding claims, wherein the stator yoke (1) is pushed as a whole at the same time over all stator teeth (3) of the stator (10).

9 stator (10) comprising a stator yoke (1) and a plurality of stator teeth (3) which carry stator windings (5) of the stator (10), characterized in that each stator tooth (3) has a connecting section (4) with at least one inclined surface (41, 42), which is located in a respective recess (2) of the stator yoke (1) of the stator which has at least one inclined surface (21, 22) (10) is received, each of the inclined surfaces (21, 22, 41, 42) of the recess (2) and connecting section (4) is structured in such a way that a jamming of the respective connecting section (4) in the respective recess (2) is improved is. Electric motor (300) with a stator (10) according to Claim 9.