Stator with elastic outer contour for electric machine

Abstract

A stator sheet (110) for a stator (100) of a rotary electric machine (200) is described, in which the stator sheet (110) has a yoke region (111) with a radially inner edge (1110) and a radially outer edge (1111), and in which a plurality of first recesses (1112) are provided in an outer region of the yoke region (111) along the radially outer edge (1111). Here, the first recess (1112) has a radially outer boundary (1116), which has a curvature in the same direction as the radially outer edge (1111), and a connecting strip (1114) is formed between the first recess (1112) and the radially outer edge (1111), which connecting strip can be elastically deformed in the radial direction to interact with a mounting surface (113a) of the stator housing (113) and exert an elastic action.

Description

Technical Field

[0001] The present invention relates to a stator sheet for a stator of a rotating electric machine, and also to a stator, an electric machine and a motor vehicle equipped with the electric machine. Background Art

[0002] The use of electric drives in motor vehicles is currently increasing rapidly, both as hybrid drives in combination with internal combustion engines and as purely electric drives. Such electric machines usually have a rotor and a stator, wherein, in the case of internal rotor electric machines, the stator is arranged in a housing and supported by the housing, which surrounds the stator from the outside. In order to achieve weight advantages, the motor housing is usually made of aluminum material. The force response (Kraftreaktion), that is, the supporting force or supporting torque, acting between the stator and the housing during the operation of the motor is essentially based on the lateral compression of the connecting partner and is very temperature-dependent. Therefore, the temperature range in which the motor can be safely operated is relatively small. However, on the other hand, the motor vehicle should be designed to be able to operate reliably within a relatively large temperature range. Here, the temperature range extends from -40°C to +85°C, and also from -45°C to +90°C. Compared with the upper temperature, the force response can increase three times at the lower temperature limit. At the lower temperature limit, the housing may be deformed as a result, and at the upper temperature limit, the stator of the motor may not be able to apply the required supporting torque and may twist, that is, slip, relative to the housing. In order to be able to transmit torque reliably under all operating conditions, a very large overlap is required between the steel sheet pack of the stator and the housing. The large overlap between stator and housing and the different coefficients of thermal expansion produce high mechanical stresses in the components. The housing must be heated up intensively during assembly. There is a risk of frustration. The rigid coupling between stator and housing, which is produced by the transverse press connection, also promotes the transmission of vibrations and noise from the motor to the drive assembly. Summary of the invention

[0003] The aim is to provide a solution that can reduce the aforementioned force response variations within a common temperature range or increase the temperature range in which the motor can operate.

[0004] This is achieved by a stator lamination according to the invention, a stator according to the invention, a corresponding electric machine and a corresponding motor vehicle.

[0005] A stator segment for a stator of a rotating electric machine is proposed, the stator segment having:

[0006] - a yoke region having a radially inner edge and a radially outer edge, and wherein

[0007] A plurality of first recesses are provided in the outer region of the yoke region along the radial outer edge, wherein:

[0008] The first recess has a radial outer boundary having a curvature in the same direction as the radial outer edge, and a connecting strip is formed between the first recess and the radial outer edge, the connecting strip being elastically deformable in a radial direction to cooperate with the mounting surface of the stator housing and exert an elastic effect.

[0009] An electric machine within the meaning of the invention can be an electric power generator and an electric drive which converts electrical energy into rotational energy to thereby drive a motor vehicle, for example. In particular, an electric machine within the meaning of the invention has an inner rotor and an outer stator.

[0010] The notch in the sense of the present invention can be a hole, a punched portion, a hole or a similar structure in the stator sheet. The connecting strip of the stator sheet has spring elasticity in the radial direction, which is pressed when installed in the stator housing. As a result, a radial elastic force that is evenly distributed substantially along the circumference acts between the stator sheet, more precisely the stator manufactured therefrom, and the stator housing. This elastic force acts over the entire operating temperature range and can at least partially compensate for the reduction in mutual extrusion force caused by the different thermal expansion of the stator sheet group and the stator housing. This has the advantage that the dependence of the stator's supporting force or force response on temperature can be reduced when the motor is running. In other words, the characteristic curve of the force response relative to the temperature can be made flatter. In particular, the radial component of the supporting force is favorably affected thereby. As a result, the motor can therefore operate reliably over a larger temperature range and a larger torque range.

[0011] Stator laminations in the sense of the present invention are thin, annular disks made of electrical sheet material, which can be formed in one piece or in multiple pieces. If a plurality of such stator laminations are stacked axially along the stator center axis or the axis of symmetry of the electric machine, an annular stator lamination package is obtained. The stator lamination package is to be installed in a stator housing.

[0012] Advantageously, for the proposed stator lamination, the radial outer edge, in particular the radial outer edge with a continuously extending contour, can be wavy, for example sinusoidal, wherein in the circumferential direction between two first notches there is respectively an outer notch, i.e. an outer notch. In this way, an arcuate, in particular convex, connecting strip is obtained, which has an increased effective length compared to the circular outer edge of the stator lamination. This means that the effective deformation range of the stator lamination relative to the stator housing is thereby increased. In particular, due to the presence of a large number of deformable connecting strips at the circumference, the effective total length of the connecting strips can exceed the circumferential length of the stator lamination.

[0013] Furthermore, it is advantageous if the connecting web in the region of the extension of the first recess can have a substantially constant width in order to achieve a flexibility or elasticity that is distributed as evenly as possible in the circumferential direction.

[0014] A further improved support of the stator laminations in the installed state can be achieved by providing a second recess radially inside the first recess in an outer region of the yoke region, wherein an elastically deformable connecting web is formed between the first and second recesses.

[0015] Another aspect of the invention relates to a stator for an electric machine, which has a plurality of stacked stator sheets according to the invention. In order to distribute the elastic forces generated by the connecting strips evenly in the stator housing, the stator sheets can be arranged within the stator sheet pack so as to be offset in the circumferential direction relative to the axially adjacent stator sheets. The stator can consist of a pack of stator sheets that are twisted relative to each other in the circumferential direction and do not completely overlap, but the stator sheets within the pack can be stacked so as to overlap.

[0016] In particular, with regard to the use of the stator as a drive source for a vehicle, the stator housing and the stator lamination package are dimensioned and joined to one another in such a way that the connecting strips of the stator laminations resting against the stator housing are elastically pressed against the stator housing over the entire operating temperature range, in particular between -45° C. and +90° C. In this way, a sufficiently high supporting force can be provided for the reaction torque of the electric machine over the entire intended range of use.

[0017] Another aspect of the invention relates to an electric machine having a stator according to the invention. Furthermore, the invention relates to a motor vehicle having an electric machine according to the invention. This has the advantage that a motor vehicle can be provided in which the electric machine can be operated more reliably or with higher performance in a predetermined operating temperature range and / or the operating temperature range of the motor vehicle can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Further advantages result from the following description, the drawings and the claims.

[0019] The attached schematic diagram is described below.

[0020] Figure 1a An embodiment of a stator sheet according to the present invention is shown;

[0021] Figure 1b Another embodiment of a stator sheet according to the present invention is shown;

[0022] Figure 2 Another embodiment of a stator sheet according to the present invention is shown;

[0023] Figure 3 Another embodiment of a stator sheet according to the present invention is shown;

[0024] Figure 4 The stator according to the invention is shown by way of example; and

[0025] Figure 5a , Figure 5b Two views of an electric machine with a stator according to the invention are shown. DETAILED DESCRIPTION

[0026] Figure 1a , Figure 1b An embodiment of a stator sheet 110 according to the invention and in particular in the form of a circular ring is shown, which is however only partially shown. The stator sheet 110 can also alternatively be formed by a plurality of circular ring segments joined together. The metal stator sheet 110 has a yoke region 111a and a tooth region 111b comprising a plurality of stator teeth, which protrude radially inward from the yoke region 111a. The stator sheet 110 has a radial inner edge 1110 and a radial outer edge 1111. Here, the radial outer edge 1111 is larger than the radial inner edge 1110. The radial outer edge 1111 is intended to cooperate with the cylindrical inner peripheral surface of the housing of the motor.

[0027] Furthermore, the stator sheet 110 has a plurality of first recesses 1112 in the yoke region 111a. Here, the recesses 1112 are arranged in the outer region of the yoke region 111a at regular intervals along the radial outer edge 1111. The first recesses 1112 have a radial outer boundary 1116, which has a curvature in the same direction as the radial outer edge 1111. A connecting strip 1114 is constructed radially between the recess 1112 and the radial outer edge 1111, which is at least partially elastic and can be deformed in particular in the radial direction. Due to its geometric structure, the connecting strip 1114 is suitable for exerting an elastic effect preferably at the radial outer edge of the stator sheet 110. At the radial outer periphery 1111 of the stator sheet 110, the press-fitting diameter is interrupted by the outer recesses 1111a, so that the press-fitting diameter is only formed by the arcuate, in particular convex, connecting strip 1114.

[0028] These outer notches at the radial outer periphery 1111 may be optional. The outer periphery 1111 may also be designed as a circumferential line as an alternative. A radial flexibility acting uniformly at the periphery is produced by a plurality of notches 1112 and associated connecting strips 1114, which on the one hand facilitates the assembly of the stator into the motor housing and on the other hand ensures reliable torque support for the stator over a wider operating temperature range.

[0029] exist Figure 1a In the embodiment, the first recess 1112a is designed as an ellipse, wherein the major axis of the ellipse is aligned with the circumferential direction of the stator sheet. Alternatively, a circular shape is also possible. Figure 1b In the embodiment, the first recess 1112b is designed to be arcuate or kidney-shaped. In both embodiments, the connecting strip 1114 has a substantially constant radial extent or width in the region of the extension of the first recess 1112a, b.

[0030] Figure 2Another embodiment of a stator sheet 110 according to the invention is shown, which is also only partially shown. Figure 2 In the stator sheet of FIG. 1 , the first notch 1112c has an arcuate portion formed in the circumferential direction and two substantially straight portions pointing in the radial direction. Therefore, the notch 1112c is generally U-shaped as a whole. The connecting strip 1114 formed at the periphery correspondingly has a section 1114a formed in the circumferential direction and two substantially radially extending sections 1114b. The radial inner boundary 1115 of the notch 1112c is designed to be wavy so that the connecting strip section 1114a can be abutted there when deformed if necessary.

[0031] Figure 1a , Figure 1b and Figure 2 The first recess 1112 shown can have a greater circumference / area ratio than an oval shape, so that a better spring effect for support in the motor housing can be achieved by the connecting web 1114 adjacent thereto.

[0032] Figure 3 Another embodiment of the stator sheet 110 according to the present invention is shown, which is basically based on Figure 2 stator sheet. Here, the stator sheet 110 has a plurality of additional second recesses 1113 in the yoke region 111. Here, the recesses 1113 are arranged to be evenly spaced in the yoke region 111, to be arranged in the outer region of the yoke region 111, and to be located radially inside the plurality of recesses 1112c. Here, the recess 1113 is, for example, circular and therefore has at least one rounded portion. The recess 1113 is bounded in the circumferential direction and radially outward by a connecting strip 1117 that is in particular elastically deformable, which further enhances the elastic effect already explained above. The plurality of second recesses 1113 are divided into recess sets 120. A recess set 120 has at least two second recesses 1113. Preferably, the center of the longitudinal axis of the recess set is arranged to be perpendicular to the center of the longitudinal side of the corresponding recess 1112 in the plurality of recesses 1112c.

[0033] Furthermore, on the side of the notch set 120 facing the corresponding notch 1112 c , the yoke region 111 is again designed to be corrugated, follows the surface of the respective second notch 1113 of the notch set 120 , and extends into the respective notch 1112 c .

[0034] Figure 4 An embodiment of a stator 100 according to the present invention is shown. The stator 100 has a plurality of stator sheets 110 according to the present invention, which are stacked along the central axis of the stator 100 and form a stator sheet group 130. Figure 4 In the example, there are Figure 3The stator laminations 110 shown. The stator laminations 110 form a transverse press connection here. The negative influence of thermal expansion on the transverse press connection can be positively influenced by the radial elastic effect of the stator laminations 110. The stator laminations 110 are arranged one after another along the stator axis and thus form a transverse press connection.

[0035] In the stator sheet group (130), the stator sheets (110) are arranged to be offset from the axially adjacent stator sheets (110) in the circumferential direction, that is, the stator sheets (110) are arranged not to overlap each other.

[0036] Specifically, in this particular embodiment, the stator sheets 110 are arranged offset with the corresponding adjacent stator sheets 110, and the offset degree is respectively an integer multiple of the length of the second notches 1113 of the notch set 120, so that the notches 1112 of the stator sheets 110 are respectively in contact with the two first notches 1112 of the corresponding adjacent stator sheets 110. Here, the second notches 1113 of the stator sheets 110 are arranged offset with the second notches 1113 of the corresponding adjacent stator sheets 110, so that the second notches 1113 of the stator sheets 110 only partially overlap with the second notches 1113 of the corresponding adjacent stator sheets 110. In addition, a closing element 112 can be provided, which covers the outer stator sheets 110.

[0037] FIG5 shows an embodiment of an electric machine 200 according to the present invention. Figure 5a The electric machine 200 is partially shown in cross section, and Figure 5b The electric machine 200 is shown in longitudinal section. Here, only the stator 100 and the housing 113 are shown.

[0038] The stator in FIG5 has a cylindrical stator housing 113 having an inner mounting surface 113a for arranging the stator 100. Here, the stator sheet 110 basically contacts the stator housing 113 vertically only at the transverse axis of the center of the longitudinal side of the corresponding recess 1112 in the plurality of recesses 1112. Figure 3 The deformation of the connecting strips 1114 of the stator laminations 110 explained and which occurs as a result when the stator 100 is installed in the stator housing 1113 compensates for the greater thermal expansion of the aluminum housing. In addition, a partial vibration decoupling can be produced between the transverse press connection and the housing.

[0039] In the case of a fluid-cooled electric machine 200 , the axial channels of the stator 100 formed by the recesses 1112 simultaneously serve as cooling channels.

[0040] With regard to the size and shape of the recess 1112 , two embodiments are basically distinguished:

[0041] In a first embodiment, the radially smallest envelope diameter generated by the recess 1112 is greater than or equal to the press-fit diameter of the stator housing 113. This results in a better thermal connection between the stator 100 and the housing 113, since after assembly, almost the entire surface of the stator 100 rests against the housing bore.

[0042] In the second embodiment, the radial smallest envelope circle diameter generated by the recess 1112 is smaller than the press-fit diameter of the stator housing 113. This results in an additional cooling channel, a poorer direct thermal connection, but better vibration decoupling.

[0043] For a better cooling design and to increase the support force of the stator 100 in the stator housing 113, an additional second recess 1113 may be introduced radially inwardly of the first recess 1112. Advantageously, the additional inner row of cooling channels is arranged opposite to the first recess 1112 forming the valley (recess). The arched structures may be distributed on the periphery and designed differently in terms of geometry. In the case where the motor 200 is fluid-cooled, it is advantageous if the spacing of the arched elements is a multiple of the sheet rotation caused by stamping. For certain embodiments of the motor 200, if the axial fluid flow through the outer region of the stator 100 is to be throttled or suppressed, this can be produced by irregular multiples between the arc distances of the sheet rotation caused by stamping.

[0044] Another solution to this problem is to close the axial channel with a non-perforated end piece or with an elastomeric closing plug.

[0045] In order to be able to optically monitor the correct sheet rotation during assembly, one or more of the arcuate elements can be designed asymmetrically or marked with notches.

[0046] List of reference numerals:

[0047] 100 Stator

[0048] 110 stator sheet

[0049] 111a Yoke area

[0050] 111b Tooth area

[0051] 112 Closure element

[0052] 113 stator housing

[0053] 113a Mounting surface

[0054] 200 Motor

[0055] 1110 Radial inner edge

[0056] 1111 Radial outer edge

[0057] 1111a External notch

[0058] 1112 First Notch

[0059] 1112a Notch

[0060] 1112b Notch

[0061] 1112c Notch

[0062] 1113 Second notch

[0063] 1114 Connecting strip

[0064] 1114a Connecting strip section

[0065] 1114b Connecting strip section

[0066] 1115 Inner Boundary

[0067] 1116 Outer Boundary

[0068] 1117 Connecting strip

[0069] 120 episodes

[0070] 130 stator sheet group

[0071] 140 Outer boundary of notch

[0072] 150 Stator centerline.

Claims

1. A stator sheet (110) for a stator (100) of a rotating electrical machine (200), wherein: The stator sheet (110) has: - a yoke region (111) having a radially inner edge (1110) and a radially outer edge (1111), and wherein - a plurality of first notches (1112) are provided in the outer region of the yoke region (111) along the radial outer edge (1111), wherein: -The first recess (1112) has a radial outer boundary (1116) with a curvature in the same direction as the radial outer edge (1111), and wherein a connecting strip (1114) is formed between the first recess (1112) and the radial outer edge (1111), and the connecting strip can be elastically deformed in the radial direction so as to cooperate with the assembly surface (113a) of the stator housing (113) and exert an elastic effect.

2. The stator sheet (110) according to claim 1, characterized in that: The radial outer edge (1111) is wave-shaped, and outer notches (1111a) are respectively formed between two first notches (1112) in the circumferential direction.

3. The stator sheet (110) according to claim 1 or 2, characterized in that: The connecting strip (1114) has a substantially constant width in the region of the extension of the first recess (1112).

4. The stator sheet (110) according to any one of claims 1 to 3, characterized in that: In the outer area of ​​the yoke area (111), a second recess (1113) is provided on the radial inner side of the first recess (1112), wherein an elastically deformable connecting strip (1117) is formed between the first recess (1112) and the second recess (1113).

5. A stator (100) for an electric machine, comprising a plurality of stator sheets (110) according to any one of the preceding claims, which are stacked axially along a stator center axis (150) and form a stator sheet group (130).

6. The stator (100) according to claim 5, characterized in that: In the stator sheet group (130), the stator sheets (110) are arranged to be offset from the axially adjacent stator sheets (110) in the circumferential direction, that is, they do not completely overlap with each other.

7. The stator (100) according to claim 5 or 6, further comprising a stator housing (113), wherein: The stator lamination package (130) is joined to the stator housing (113) so that the connecting strips (1114) of the stator laminations (110) which are in contact with the stator housing (113) are elastically pressed against the stator housing (113) over the entire operating temperature range, in particular between -45°C and +90°C.

8. An electric machine (200) comprising a stator (100) according to any one of claims 5 to 7.

9. A motor vehicle comprising an electric machine (200) according to claim 8.

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