Stator device, associated production method and electric machine for an electrically driveable vehicle

Abstract

A stator device (10) that has a longitudinal axis (11) and comprises: - a stator core (12), which has a first end face (13), a second end face (14) situated axially opposite the first end face (13), and an outer lateral surface (15) and forms a plurality of fastening openings (16) distributed in the circumferential direction and extending axially through the stator core (12); - a stator housing (18), which has an inner lateral surface (19) facing the outer lateral surface (15) and, at an axial position (20), a stop which faces the first end face (13) and prevents an axial movement of the stator core (12) on one side, wherein the inner lateral surface (19) has, along a first axial region (21) in a plurality of sectors (32a-f) which each extend between a pair of fastening openings (16) adjacent to one another in the circumferential direction, a first inside radius which forms a radial gap (26) between the outer lateral surface (15) and the inner lateral surface (19); and - fastening elements (17), which pass through the fastening openings (16) and brace the stator core (12) against the stator housing (18); wherein the inner lateral surface (19) has, in the sectors (32a-f) along a second axial region (22) which extends between the first axial region (21) and the axial position (20), a second inside radius which is smaller than the first inside radius and centres the first end face (13) in the stator housing (18) in relation to the longitudinal axis (11).

Description

[0001] Stator device, associated manufacturing method and electric machine for an electrically driven vehicle

[0002] The present invention relates to a stator device with a longitudinal axis, comprising: a stator core having a first end face, a second end face axially opposite the first end face, and an outer surface, and forming a plurality of fastening openings distributed in the circumferential direction and extending axially through the stator core; a stator housing having an inner surface facing the outer surface and, at an axial position, a stop which faces the first end face and by which an axial movement of the stator core is inhibited on one side, wherein the inner surface has a first inner radius along a first axial region in a plurality of sectors, each of which extends between a pair of fastening openings adjacent in the circumferential direction, through which a radial gap is formed between the outer surface and the inner surface;and fastening elements that pass through the fastening holes and clamp the stator core to the stator housing.;

[0003] In addition, the invention relates to a method for producing a stator device and an electric machine for an electrically driven vehicle.

[0004] It is known to accommodate stators in a stator housing to form a stator device, such that an inner circumferential surface of the stator housing and an outer circumferential surface of a stator core face each other. Instead of fastening the stator core by means of a press fit in the stator housing, it is also known to use fastening elements that axially penetrate fastening openings in the stator core. The radii of the circumferential surfaces are typically dimensioned such that a radial gap exists between the circumferential surfaces during insertion of the stator core into the stator housing in order to enable axial mobility of the stator core. However, such a gap makes it difficult to arrange the stator core and the stator housing precisely coaxially along a longitudinal axis of the stator device.In particular, if these components are arranged with insufficient precision, undesirable vibrations may occur during operation of an electrical machine having the stator device.

[0005] The invention is based on the object of providing an improved possibility for arranging a stator core in a stator housing.

[0006] This object is achieved according to the invention by a stator device of the type mentioned at the outset, in which the inner circumferential surface in the sectors along a second axial region extending between the first axial region and the axial position has a second inner radius which is smaller than the first inner radius and by means of which the first end face is centered with respect to the longitudinal axis in the stator housing.

[0007] The invention is based on the idea of ​​deliberately reducing the inner radius to the second inner radius in selected angular regions of the inner surface, namely in the sectors between the fastening openings, in order to enable centering when inserting the stator core into the stator housing. This allows corresponding longitudinal axes of the stator core and the stator housing to be aligned more precisely relative to the longitudinal axis of the stator device, at least in the second axial region, and the stator core to be precisely centered in the stator housing. This counteracts, in particular, the generation of unwanted vibrations during rotating operation of an electrical machine having the stator device.

[0008] The stator core can be formed from a plurality of axially stacked and / or mutually electrically insulated individual laminations. In this respect, the stator core can also be referred to as a stator lamination stack. The stator device can further comprise a stator winding that extends partially through slots formed in the stator core. The stator winding can form a winding head at each end face.

[0009] The stator winding can be a round wire winding accommodated in the stator core.

[0010] The stator winding can be a shaped conductor winding accommodated in the stator core. The shaped conductors can have a rectangular cross-section and the shape of a U-pin or L-pin. A U-pin is formed in one piece and has two conductor legs that can be accommodated in different slots in the stator core. At their free ends, which protrude from one end face of the stator core, the shaped conductors can be connected to adjacent, further shaped conductors. At the other end face, they are connected to each other in pairs and as a single piece. An L-pin has two free ends that protrude from the slot on opposite end faces of the stator core and can be connected to the free ends of adjacent shaped conductors.

[0011] In a preferred embodiment of the stator device according to the invention, the second axial region extends to the axial position.

[0012] It is particularly advantageous if the second axial region in the stator device according to the invention comprises at most one-tenth, preferably at most one-twentieth, of the axial extent of the stator core. Alternatively or additionally, the axial extent of the second axial region can be two to ten millimeters, in particular three to six millimeters. Due to such a short design of the second axial region, the stator core only needs to be guided over a short distance along the second radius when inserted into the stator device, thereby preventing undesirable chip formation and simultaneously achieving good centering. Furthermore, damage and / or high press-in forces can be avoided.In a preferred development of the stator device according to the invention, a third axial region adjoins the second axial region in the direction of the second end face, along which the inner lateral surface has an inner radius profile in the sectors, forming a chamfer. The chamfer facilitates the insertion of the stator core into the stator housing. In this case, in particular, the first axial region adjoins the third axial region.

[0013] Alternatively, the first axial region can be arranged adjacent to the second axial region. This facilitates the production of the stator housing, as it has a less complex geometry.

[0014] Particularly preferably, a transition from the first axial region to the third axial region and / or a transition from the second axial region to the third axial region is / are rounded and / or formed with a broken edge. Such an edgeless design reduces the risk of undesirable chip formation.

[0015] The stator device according to the invention can further comprise a cooling device configured to convey a cooling fluid along a cooling channel for cooling the stator device, wherein the cooling channel extends partially through the gap. The cooling fluid can be liquid and comprise, for example, water, oil, or a coolant. However, the cooling fluid can also be gaseous.

[0016] In the stator device according to the invention, it can further be provided that a fourth axial region adjoins the second axial region in the direction pointing away from the second end face, along which fourth axial region the inner circumferential surface in the sectors continues to have the second inner radius. By widening the sections in which the inner circumferential surface has the second inner radius, for example, an escape of the cooling fluid can be facilitated. In particular, spray cooling of the winding overhangs can be formed in this way. In a further development, it can be provided that a fifth axial region adjoins the fourth axial region, along which fifth axial region the inner circumferential surface in the sectors has a third inner radius that is smaller than an outer radius of the stator core at the first axial position in the sectors.

[0017] In the stator device according to the invention, it is advantageous with regard to the stator if the outer circumferential surface in the sectors forms recesses extending from the first end face to the second end face, which enlarge the gap at their respective positions in the circumferential direction. Through these recesses, for example, the cooling fluid can be guided to an outlet point for the aforementioned spray cooling of the winding heads with a lower flow resistance or a larger volume flow.

[0018] Furthermore, in a preferred embodiment of the stator device according to the invention, the outer circumferential surface in second sectors, each of which lies between a pair of adjacent first sectors, has an outer radius profile that is enlarged compared to an outer radius of the outer circumferential surface in the first sectors such that the fastening opening lies at least partially outside the outer radius in the first sectors. The outer circumferential surface can accordingly be provided with radial bulges in which the fastening openings are formed - completely or partially. This creates sufficient radial space even for relatively large fastening openings or fastening means, without influencing an inner radial region of the stator core in which slots for the stator winding are formed.

[0019] Particularly preferably, it is provided that the outer circumferential surface and / or the inner circumferential surface has / have a projection in one of the second sectors in the second axial region. The projection can form a press fit between the outer circumferential surface and the inner circumferential surface. The projection can determine a rotational position of the stator core within the stator housing. In particular, no press fit is formed in the other of the second sectors along the second axial region and / or the gap is formed outside of one of the second sectors. This makes it possible to avoid static overdetermination and undesirable constraining forces when determining the rotational position.

[0020] Alternatively, it is also possible that the gap is also formed in the second sectors.

[0021] In detail, it can further be provided that the inner lateral surface along the fourth axial region and / or the fifth axial region in the second sectors has an inner radius which is smaller than the outer radius of the stator core at the axial in the second sectors.

[0022] The object underlying the invention is further achieved by a method for producing a stator device, comprising the following steps: providing a stator core which has a first end face, a second end face axially opposite the first end face, and an outer circumferential surface, and which forms a plurality of fastening openings distributed in the circumferential direction and extending axially through the stator core; providing a stator housing which has an inner circumferential surface and a stop at an axial position, wherein the inner circumferential surface has a first inner radius along a first axial region in a plurality of sectors and has a second inner radius, which is smaller than the first inner radius, in the sectors along a second axial region extending between the first axial region and the axial position;Inserting the stator core into the stator housing until the stop facing the first end face inhibits axial movement of the stator core on one side, wherein the outer circumferential surface faces the inner circumferential surface, the sectors each extend between a pair of circumferentially adjacent fastening openings of the stator core, a radial gap is formed between the outer circumferential surface and the inner circumferential surface, and the first end face is centered in the stator housing with respect to the longitudinal axis by the second inner radius; and clamping the stator core to the stator housing by means of fastening elements which penetrate the fastening openings.

[0023] In particular, within the scope of the method according to the invention, it can be provided that the outer lateral surface in second sectors, which are each located between a pair of adjacent first sectors, has an outer radius profile which is enlarged compared to an outer radius of the outer lateral surface in the first sectors such that the fastening opening lies at least partially outside the outer radius in the first sectors, wherein in the step of inserting the stator core, the outer lateral surface and the inner lateral surface in one of the second sectors form a press fit along the second axial region and thus a rotational position of the stator core in the stator housing is determined.

[0024] All embodiments of the stator device according to the invention can be transferred analogously to the method according to the invention, so that the aforementioned advantages can also be achieved with this method.

[0025] The object underlying the invention is further achieved by an electric machine for an electrically driven vehicle, comprising a rotor and a stator device according to the invention or a stator device obtained by a method according to the invention, wherein the rotor is rotatably mounted with respect to the stator device and the electric machine is designed to drive the vehicle.

[0026] Further advantages and details of the present invention will become apparent from the following drawings. These are schematic representations and show:

[0027] Fig. 1 is a sectional schematic diagram of an embodiment of the electrical device according to the invention with an embodiment of the stator device according to the invention; Fig. 2 is a perspective view of the stator core of the stator device according to the embodiment;

[0028] Fig. 3 is a sectional view of the stator device along a sectional plane III-III in Fig. 1;

[0029] Fig.4 is a sectional detailed view of the stator core and the stator housing in the region of one of the first sectors;

[0030] Fig. 5 is a perspective detailed view of the inner surface in the region of one of the first sectors;

[0031] Fig. 6 is a perspective detailed view of the inner surface in the region of one of the second sectors; and

[0032] Fig. 7 is a flow chart of an embodiment of the manufacturing method according to the invention.

[0033] Fig. 1 is a sectional schematic diagram of an embodiment of an electrical machine 1 with an embodiment of a stator device 10.

[0034] In addition to the stator device 10, the electric machine 1 has a rotor 2 that is rotatably mounted relative to the stator device 10, and a shaft 3 that is connected to the rotor 2 in a rotationally fixed manner. The electric machine 1 is, for example, a permanently or electrically excited synchronous motor or an asynchronous motor. The electric machine 1 is designed to drive an electrically driven vehicle (not shown), for example a battery-electric vehicle, a hybrid vehicle, or a fuel cell vehicle. The stator device 10, the longitudinal axis 11 of which is shown in dash-dotted lines, has a stator core 12 with a first end face 13, with a second end face 14 axially opposite it, and with an outer circumferential surface 15. Not visible in Fig. 1 are fastening openings 16 that extend axially through the stator core 12 (see Fig. 2), which are penetrated by fastening elements 17.

[0035] The stator device 10 further comprises a stator housing 18 with an inner surface 19 facing the outer surface 15 of the stator core 12. At an axial position 20, the stator housing 18 has a stop. For purely qualitative purposes, a first axial region 21 and a second axial region 22 of the stator device 10 as well as optional third, fourth, and fifth axial regions 23, 24, 25 of the stator device 10 are also shown. A gap—not visible in Fig. 1—between the outer surface 15 and the inner surface 19 is provided with the reference numeral 26. Purely by way of example, the axial extent of the stator core 12 in the present exemplary embodiment is 120 mm, and the axial extent of the second axial region 22 is 4 mm.

[0036] As further optional components of the stator device 10, Fig. 1 also shows, purely schematically, winding heads 27 of a stator winding of the stator device 10 and a cooling device 28 configured to convey a cooling fluid along a cooling channel 29 for cooling the stator device. The cooling channel 29 extends partially through the gap 26.

[0037] Fig. 2 is a perspective view of the stator core 12 of the stator device 10 according to the embodiment.

[0038] A plurality of circumferentially arranged slots 30 are formed in the stator core 12, in which the stator winding is accommodated in sections. Also visible are the fastening openings 16, which in the present exemplary embodiment are six. Optionally, the outer surface 15 forms recesses 31 that extend from the first end face 13 to the second end face 14. At their respective positions in the circumferential direction, the recesses 31 radially enlarge the gap 26.

[0039] Fig. 3 is a sectional view of the stator device 10 along a sectional plane III-III in Fig. 1, whereby the stator winding has been omitted for reasons of clarity. Thus, it shows a view of the second end face 14 of the stator core 12 accommodated in the stator housing 18.

[0040] The stator device 10 is divided into six first sectors 32a to 32f relative to the longitudinal axis 11. Each of the first sectors 32a to 32f extends between a pair of circumferentially adjacent mounting openings 16.

[0041] In Fig. 3, it can also be seen in the detailed design of this exemplary embodiment that the outer circumferential surface 15 of the stator core 12 is subdivided into six second sectors 33a to 33f. Each second sector 33a to 33f lies between a pair of adjacent first sectors 32a to 32f. In the second sectors 33a to 33f, an outer radius of the outer circumferential surface 15 is enlarged compared to an outer radius in the first sectors 33a to 33f such that the fastening openings 16 lie at least partially outside the outer radius in the first sectors 32a to 32f. In this way, figuratively speaking, ear-shaped bulges of the stator core 12 are formed. In the present exemplary embodiment, the central angles of the first and second sectors 32a to 32f, 33a to 33f add up to 360°.

[0042] Fig. 4 is a sectional detailed view of the stator core 12 and the stator housing 18 in the region of one of the first sectors 32a to 32f. Fig. 5 is a perspective detailed view of the inner circumferential surface 19 in the region of one of the sectors 32a. Along the first axial region 21, the inner circumferential surface 19 in the first sectors 32a to 32f has a first inner radius through which the gap 26 between the outer circumferential surface 15 and the inner circumferential surface 19 is formed. Along the second axial region 22, the inner circumferential surface 19 in the first sectors 32a to 32f has a second inner radius which is smaller than the first inner radius, as a result of which the first end face is centered in the stator housing 18 with respect to the longitudinal axis 11 (see Fig. 1).

[0043] The third axial region 23 lies between the first axial region 21 and the second axial region 22 and adjoins these axial regions 21, 22. Along the third axial region 23, the inner circumferential surface 19 has an inner radius profile forming a chamfer 34 in the first sectors 32a to 32f.

[0044] In the direction away from the second end face 14, the fourth axial region 24 adjoins the second axial region 22. Along the fourth axial region 24, the inner circumferential surface 19 continues to have the second inner radius in the first sectors 32a to 32f.

[0045] The fourth axial region 24 is adjoined by the fifth axial region 25. Along the fifth axial region 25, the inner lateral surface 19 in the first sectors 32a to 32f has a third inner radius that is smaller than an outer radius of the stator core 12 at the first axial position 20 in the sectors 32a to 32f.

[0046] In the second sectors 33a to 33f, the inner circumferential surface 19 along the fourth and fifth axial regions 24, 25 may have an inner radius that is smaller than the outer radius of the stator core 12 at the first axial position 20 in the sectors 33a to 33f.

[0047] In detail, the first axial region 21 extends from the third axial region 23 to the second end face 14. The second axial region extends from the axial position 20 to the third axial region 23. The fourth axial region 24 extends from the axial position 20 to the fifth axial region 25. One of the recesses 31 is also shown in dashed lines in Fig. 4. Due to the continuation of the second inner radius in the fourth axial region 24, the cooling fluid located in the gap 26 in the region of the recess 31 on the first end face 13 can leave the gap 26 and enable spray cooling for the winding overhangs 27 (see Fig. 1).

[0048] Fig. 6 is a perspective view of the inner surface 19 in the region of one of the second sectors 33a.

[0049] In the second sector 33a, the outer surface 15 and the inner surface 19 form a press fit along the second axial region 22, thus allowing the rotational position of the stator core 12 to be determined relative to the stator housing 18. For this purpose, the inner surface 19 in the second sector 33a has a projection 34a in the second axial region 22. Such a projection is not provided in the remaining second sectors 33b to 33f, so that the rotational position can be determined without static overdetermination and constraining forces. According to alternative embodiments, the projection 34a can also be provided in the outer surface 15 or in both surfaces 15, 19.

[0050] In the present exemplary embodiment according to Fig. 1, the stator housing 18 has a first housing part 35 and a second housing part 36. The first housing part 35 forms a first bearing shield 37 and the inner circumferential surface 19. The second housing part 36 forms a second bearing shield 38 and closes the first housing part 35. The first bearing shield 37 is a drive end shield. The second bearing shield 38 is a non-drive end shield. The first end face 13 faces the first bearing shield 37.

[0051] A method for manufacturing a stator device 10 will be described below, with reference to the preceding embodiment. Figure 7 is a flowchart of an embodiment of the manufacturing method.

[0052] The method includes a step S10 of providing the stator core 11. Furthermore, the stator housing 18 is provided in a step S20.

[0053] In a step S30, the stator core 11 is inserted into the stator housing 18 until the stop facing the first end face 13 inhibits an axial movement of the stator core 11 on one side and such that the outer circumferential surface 15 faces the inner circumferential surface 19, the first sectors 32a to 32f lie between the fastening openings and the radial gap 26 is formed between the outer circumferential surface 15 and the inner circumferential surface 19. In this case, the second inner radius centers the first end face 13 with respect to the longitudinal axis 11 in the stator housing 18. In addition, a rotational position of the stator core 12 in the stator housing 18 is determined by the press fit in the second sector 33a.

[0054] In a subsequent step S40, the stator core 11 is clamped to the stator housing 18 by means of the fastening elements 17 which pass through the fastening openings 16.

Claims

Patent claims 1 . Stator device (10) with a longitudinal axis (1 1 ), comprising: - a stator core (12) having a first end face (13), a second end face (14) axially opposite the first end face (13) and an outer circumferential surface (15) and forming a plurality of fastening openings (16) arranged distributed in the circumferential direction and extending axially through the stator core (12); a stator housing (18) having an inner surface (19) facing the outer surface (15) and, at an axial position (20), a stop which faces the first end face (13) and by which an axial movement of the stator core (12) is inhibited on one side, wherein the inner surface (19) has a first inner radius along a first axial region (21) in several sectors (32a-f), each extending between a pair of circumferentially adjacent fastening openings (16), through which a radial gap (26) is formed between the outer surface (15) and the inner surface (19); and Fastening elements (17) which pass through the fastening openings (16) and clamp the stator core (12) to the stator housing (18); characterized in that the inner circumferential surface (19) in the sectors (32a-f) along a second axial region (22) which extends between the first axial region (21) and the axial position (20) has a second inner radius which is smaller than the first inner radius and by means of which the first end face (13) is centered with respect to the longitudinal axis (11) in the stator housing (18).

2. Stator device according to claim 1, wherein - the second axial region (22) extends to the axial position (20) and / or - the second axial region (22) comprises at most one tenth, preferably at most one twentieth of the axial extent of the stator core (12) and / or - an axial extension of the second axial region (22) is two to ten millimeters, in particular three to six millimeters.

3. Stator device according to claim 1 or 2, wherein the second axial region (22) is adjoined in the direction of the second end face (14) by a third axial region (23), along which the inner circumferential surface (19) in the sectors (32a-f) has an inner radius profile forming a chamfer (34).

4. Stator device according to claim 3, wherein the first axial region (21) adjoins the third axial region (23).

5. Stator device according to claim 1 or 2, wherein the first axial region (21) adjoins the second axial region (22).

6. Stator device according to one of the preceding claims, further comprising a cooling device (28) which is designed to convey a cooling fluid along a cooling channel (29) for cooling the stator device (10), wherein the cooling channel (29) extends in sections through the gap (26).

7. Stator device according to one of the preceding claims, wherein the second axial region (22) is adjoined in the direction pointing away from the second end face (14) by a fourth axial region (24), along which the inner circumferential surface (19) in the sectors (32a-f) continues to have the second inner radius, wherein the fourth axial region (24) is adjoined by a fifth axial region (25), along which the inner circumferential surface (19) in the sectors (32a-f) has a third inner radius which is smaller than an outer radius of the stator core (12) at the axial position (20) in the sectors (32a-f).

8. Stator device according to one of the preceding claims, wherein the outer circumferential surface (15) forms recesses (31) in the sectors (32a-f) extending from the first end face (13) to the second end face (14), which enlarge the gap (26) at their respective positions in the circumferential direction.

9. Stator device according to one of the preceding claims, wherein the outer circumferential surface (15) in second sectors (33a-f), which each lie between a pair of adjacent first sectors (32a-f), has an outer radius profile which is enlarged compared to an outer radius of the outer circumferential surface (15) in the first sectors (32a-f) such that the fastening opening (16) lies at least partially outside the outer radius in the first sectors (32a-f).

10. Stator device according to claim 9, wherein the outer circumferential surface (15) and / or the inner circumferential surface (19) has a projection (34a) in one of the second sectors (33a-f) in the second axial region (22). 1 1. Stator device according to claim 10, wherein the projection (34a) forms a press fit between the outer circumferential surface (15) and the inner circumferential surface (19).

12. Stator device according to claim 10 or 11, wherein the projection (34a) determines a rotational position of the stator core (12) within the stator housing (18).

13. Stator device according to one of the preceding claims, further comprising a stator winding which extends in sections through slots (30) formed in the stator core (12).

14. A method for producing a stator device (10), comprising the following steps: Providing a stator core (12) which has a first end face (13), a second end face (14) axially opposite the first end face (13) and an outer circumferential surface (15) and forms a plurality of fastening openings (16) distributed in the circumferential direction and extending axially through the stator core (12); Providing a stator housing (18) having an inner circumferential surface (19) and a stop at an axial position (20), wherein the inner circumferential surface (19) has a first inner radius along a first axial region (21) in a plurality of sectors (32a-f) and has a second inner radius, which is smaller than the first inner radius, in the sectors (32a-f) along a second axial region (22) extending between the first axial region (21) and the axial position (20); Inserting the stator core (12) into the stator housing (18) until the stop facing the first end face (13) inhibits an axial movement of the stator core (12) on one side, wherein the outer circumferential surface (15) faces the inner circumferential surface (19), the sectors (32a-f) each extend between a pair of circumferentially adjacent fastening openings (16) of the stator core (12), a radial gap (26) is formed between the outer circumferential surface (15) and the inner circumferential surface (19), and the first end face (13) is centered in the stator housing (18) with respect to the longitudinal axis (11) by the second inner radius; and clamping the stator core (12) to the stator housing (18) by means of fastening elements (17) which pass through the fastening openings (16).

15. The method according to claim 14, wherein the outer surface (15) in second sectors (33a-f), each of which lies between a pair of adjacent first sectors (32a-f), has an outer radius profile which is enlarged compared to an outer radius of the outer surface (15) in the first sectors (32a-f) such that the fastening opening (16) lies at least partially outside the outer radius in the first sectors (32a-f), wherein in the step of inserting the stator core (12), the outer surface (15) and the inner circumferential surface (19) forms a press fit in one of the second sectors (33a-f) along the second axial region (22), thus determining a rotational position of the stator core (12) in the stator housing (18).

16. An electrical machine (1) for an electrically driven vehicle, comprising a rotor (2) and a stator device (10) according to any one of claims 1 to 13 or a stator device (10) obtained by a method according to claim 14 or 15, wherein the rotor (2) is rotatably mounted with respect to the stator device (10) and the electrical machine (1) is configured to drive the vehicle.

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