Electric machine with stator sleeve anti-rotation device

Abstract

The invention relates to an electric machine with an assembly consisting of a stator sleeve (17) and a stator lamination stack (15), in which the stator sleeve (17) is inserted into a hollow cylindrical electric machine housing (1) in a rotationally secure manner. According to the invention, the stator sleeve (17) is extended in the axial direction by at least one locking element (27). The locking element (27) is positively engaged with a counter contour (31) on the housing side, thereby providing a rotational locking mechanism for the stator sleeve (17) relative to the electric machine housing (1).

Description

[0001] The invention relates to an electric machine according to the preamble of claim 1.

[0002] In an electric machine, the stator can either be inserted directly into a hollow cylindrical electric machine housing, or alternatively a two-stage assembly process can be carried out in which in a first assembly step a stator laminated core is pressed into a stator sleeve and in a subsequent second assembly step the assembly consisting of the stator sleeve and the stator laminated core pressed into it is mounted in the electric machine housing.

[0003] In a generic electric machine, the assembly consisting of the stator sleeve and stator laminated core is inserted into a hollow cylindrical electric machine housing in a rotationally secure manner. To ensure rotationally secure positioning of the assembly consisting of the stator sleeve and stator laminated core in the electric machine housing, the stator sleeve can, for example, be pressed into the electric machine housing, welded to it, or alternatively screwed to it. However, such an anti-rotation device is associated with an excessively large amount of installation space in the state of the art. The following fact must also be considered: The stator sleeve is deformed by the pressing in of the stator laminated core. The anti-rotation device located between the stator sleeve and the electric machine housing must therefore be designed in a complex manner so that tolerances due to stator sleeve deformation can be compensated.

[0004] DE 10 2020 114 748 A1 discloses an electric machine with a stator connected to the housing. The stator core is secured to a first bearing plate of the electric machine housing via several screws on its axial side. DE 10 2021 122 580 A1 discloses a method for manufacturing a rotor with an axial securing concept. FR 3 072 223 B1 discloses an electric machine. Its stator is arranged in a housing consisting of two housing parts that are axially clamped together by screws.

[0005] The object of the invention is to provide an electric machine in which the anti-twist device of the stator sleeve in the electric machine housing can be implemented in a structurally simple manner compared to the prior art and with a sufficiently large tolerance compensation.

[0006] The object is solved by the features of claim 1. Preferred developments of the invention are disclosed in the subclaims.

[0007] The invention is based on an electric machine with a cylindrical stator sleeve into which a stator laminated core is pressed during a joining process. The assembly comprising the stator sleeve and stator laminated core is inserted into a hollow cylindrical electric machine housing in a rotationally secure manner. According to the characterizing part of claim 1, the rotation lock of the stator sleeve to the electric machine housing is provided as follows: The stator sleeve is extended in the axial direction by at least one locking element. The locking element projects beyond an end edge of the stator sleeve with an axial height. In the assembled state, the locking element is in positive engagement with a counter contour on the housing side. The rotation lock according to the invention is thus arranged in axial alignment with the stator sleeve, is structurally simple and requires less installation space. In particular, no additional installation space is required on the radially outer and / or radially inner side of the stator sleeve.

[0008] In a technical implementation, the securing element can be a separate component from the stator sleeve that can be connected to the stator sleeve. In this way, the stator sleeve can be provided largely in a conventional sleeve geometry, which only needs to provide an additional connection point for the securing element. In a specific design variant, the securing element can be a screw bolt. In the assembled state, the screw bolt is screwed to the electric machine housing with its bolt shank to ensure anti-rotation protection.

[0009] A screw connection that is preferred with regard to the anti-twist protection and the required tolerance compensation is designed as follows: The bolt shank can protrude through a cylindrical bolt passage in the electric machine housing and its bolt tip can be in threaded engagement with a screw nut on the outside of the housing.

[0010] The stator sleeve can, for example, be made of an aluminum material. Its component rigidity is reduced compared to the component rigidity of the stator laminated core, so that the stator sleeve inevitably adapts to the outer contour of the stator laminated core when the stator laminated core is pressed in and may deform. Due to the deformation of the stator sleeve, the positioning and / or alignment of the screw bolt can be subject to component tolerances. Against this background, it is preferred if the screw bolt is guided through the housing-side bolt opening to the outside of the housing with a sufficiently large hole clearance. The hole clearance is preferably dimensioned such that tolerance-related position deviations of the screw bolt can be compensated. If necessary, the screw bolt can therefore be guided off-center through the bolt opening to compensate for the tolerance.

[0011] To ensure a secure connection to the stator sleeve, the screw bolt can have a bolt head with a larger cross-section than the bolt shaft, which can be connected to the stator sleeve. In the assembled state, the cylindrical bolt opening on the housing side can thus be clamped between the screw nut and the bolt head. In the assembled state, the bolt head, with its head contact surface, can also be in axial pressure contact with an opening edge area of ​​the housing-side bolt opening.

[0012] The opening edge area of ​​the housing-side bolt passage can act as a movement stop during assembly of the stator sleeve in the electric machine housing as follows: During assembly, the assembly, consisting of the stator sleeve with the stator laminated core pressed into it, is retracted axially into the electric machine housing until the head contact surface of the bolt head comes into contact with the opening edge area of ​​the housing-side bolt passage. In this state, the screw bolt protrudes outward through the housing-side bolt passage, allowing its shank tip to be screwed onto the screw nut on the outside of the housing.

[0013] For increased anti-twist protection, the bolt head can have an anti-twist profile on its contact surface, such as a web or similar. During assembly, the anti-twist profile can engage the facing edge of the bolt opening on the housing side, i.e., be driven into the material of the electric machine housing.

[0014] The bolt head can be attached to the stator sleeve in different ways: In a first embodiment, the bolt head can have an external thread that can be brought into engagement with a nut thread formed on the stator sleeve. In a second embodiment, a press connection can be implemented instead of such a screw connection, in which the bolt head of the screw bolt can be pressed axially into a recess in the stator sleeve. Such a press connection can be implemented with significantly less installation space than a screw connection: For example, the recess in the stator sleeve cannot be implemented as a blind hole or the like. Instead, the recess that cooperates with the bolt head in a press fit can be a groove-shaped recess that is machined into the stator sleeve edge. The groove-shaped recess can be set back axially from the stator sleeve edge by one groove depth.

[0015] In a particularly space-saving design variant, the groove-shaped recess incorporated into the stator sleeve edge can be open both radially inward and radially outward. In this case, only the groove flanks of the groove-shaped recess, which extend upwards from the groove base to the stator sleeve edge, are press-fitted with the bolt head.

[0016] The bolt head can also be flattened on its radially inner and outer sides, forming flat sides. As a result, the bolt head, with its two flat sides, does not protrude beyond the groove-shaped recess in the stator sleeve, or only does so with a slight oversize, thus saving installation space. The bolt head can also have knurling, particularly on its narrow sides. In addition to the interference fit, this knurling can be brought into material engagement with the two groove flanks of the groove-shaped recess machined into the stator sleeve edge.

[0017] An embodiment of the invention is described below with reference to the accompanying figures. They show: Fig. 1 to 7 are views illustrating an anti-twist device for the stator sleeve in an electric machine housing.

[0018] In the Fig. 1 shows a partial sectional view of an electric machine in the assembled state to the extent necessary for understanding the invention. Accordingly, the electric machine has a two-part electric machine housing 1 consisting of two approximately pot-shaped housing parts 3, 5. Of the two housing parts 3, 5, Fig. 1, the left-side housing part 3 is formed from an end wall 7 and an adjoining cylindrical peripheral wall 9. The peripheral wall 9 merges at a flange connection 11 into a peripheral wall 13 of the right-side housing part 5. A stator laminated core 15 is positioned in the hollow-cylindrical electric machine housing 1, with a stator sleeve 17 interposed therebetween. The stator laminated core 15 is provided with a coil winding 18 (only schematically indicated), the winding heads 19 of which protrude into a winding head space 21 of the electric machine housing 1, which extends axially between the housing-side end wall 7 and the end face of the stator laminated core 15. The stator laminated core 15 interacts with a rotor 22, the rotor shaft 23 of which is rotatably mounted on a bearing point 25 of the housing-side end wall 7 of the left-side housing part 3.

[0019] As from the Fig. 1, the stator sleeve 17 is extended in the axial direction by a screw bolt 27, which is connected with its bolt head 26 by a press fit to a connection point 29 of the stator sleeve edge 28. The screw bolt 27 is part of a rotation lock of the stator sleeve 17 to the electric machine housing 1. In addition, the screw bolt 27 projects beyond the frontal stator sleeve edge 28 by an axial height a ( Fig. 3). In the Fig. 1, the screw bolt 27 is provided with a housing-side counter-contour 31 ( Fig. 1) in a form-locking connection, which ensures that the stator sleeve 17 is secured against rotation relative to the electric machine housing 1.

[0020] In the Fig. 1 or Fig. 2, the screw bolt 27, with its bolt shank 33 and hole clearance s, is guided through a hollow cylindrical bolt passage 35 on the housing side. This is formed on the end wall 7 of the left-hand housing part 3. The bolt tip of the screw bolt 27 is in threaded engagement with a screw nut 37 on the outside of the housing. Accordingly, the bolt passage 35 formed on the housing part 3 is clamped in the axial direction between the screw nut 37 and the bolt head 26 of the screw bolt 27.

[0021] Due to the limited space available in the electric machine housing 1, the anti-twist device must be implemented in the most space-efficient manner possible. Against this background, the connection point 29, at which the bolt head 35 is connected to the stator sleeve edge 28, is implemented as follows with a view to package optimization: Accordingly, the bolt head 26 is pressed into a recess 39 in the stator sleeve 28 in the axial direction. The recess 39 is not machined as a space-intensive blind hole in the stator sleeve edge 28. Rather, the recess 39 is designed according to the Fig. 4 is realized as a groove-shaped recess formed in the stator sleeve edge 28. Its groove bottom 41 is axially recessed from the stator sleeve edge 28 by a groove depth t.

[0022] From the groove bottom 41 to the stator sleeve edge 28, groove flanks 43 are raised axially. In the area of ​​the groove-shaped recess 39, the material thickness of the housing part 3 is reduced by an allowance d ( Fig. 4). In addition, the groove-shaped recess 39 is designed to be open radially inward and radially outward, so that only the groove flanks 43 raised from the groove bottom 41 come into a press fit with the bolt head 26.

[0023] The bolt head 26 is further flattened radially inward and radially outward, each forming flat sides 45, while the bolt head 26 can only be brought into press contact with the two groove flanks 43 of the groove-shaped recess 39 of the stator sleeve 28 by means of its narrow sides 47. Due to the flattening on both sides, the bolt head 26 does not project beyond the groove-shaped recess 39 formed in the stator sleeve 17 radially inward and radially outward, or only with a slight oversize m ( Fig. 7).

[0024] To further increase the strength of the connection between the bolt head 26 and the stator sleeve 17, the bolt head 26 has a knurling on its two narrow sides 47, which can be brought into material engagement with the two groove flanks 43 of the groove-shaped recess 39. The knurling formed on the bolt head 26 extends towards the top of the bolt head into a shoulder 49 with a reduced cross-section ( Fig. 5 or Fig. 6). In the assembled state, this defines, together with the groove bottom 41 of the recess 39 of the stator sleeve 17, a space which serves as a chip catcher.

[0025] As from the Fig. 5, the bolt head 26 has at its opening edge area 46 (only in the Fig. 7) of the bolt head passage 35, has an anti-twist profile 51, which is implemented as a web-shaped projection. In the assembled state, the web-shaped projection 51 is in material engagement with the opening edge region 46 of the cylindrical bolt passage 35.

[0026] The following is based on the Fig.7 describes a process sequence for assembling the electric machine: Accordingly, a press-in process first takes place, in which the stator laminated core 15 is pressed into the stator sleeve 17. Before or after this joining process, the screw bolt 27 is pressed with its bolt head 26 into the groove-shaped recess 39 of the stator sleeve edge 28. This is followed by a further joining process, in which the assembly comprising stator sleeve 17 and stator laminated core 15 is inserted in the direction of the arrow into the left-hand housing part 3 until the head support surface 44 of the bolt head 26 comes into contact with the opening edge region 46 of the housing-side bolt passage 35. During this insertion process, the screw bolt 27 with its bolt shank 33 is simultaneously guided outwards through the housing-side bolt passage 35.

[0027] It should be noted that the stator sleeve 17 is deformed by the pressing-in of the stator laminated core 15, which means that the positioning and / or alignment of the screw bolt 27 is subject to tolerances. Accordingly, the hole clearance s between the bolt passage 35 and the screw bolt 27 is sufficiently large to easily compensate for such tolerances. Thus, the screw bolt 27 can, for example, be guided off-center through the housing-side bolt passage 35 to compensate for tolerances.

[0028] The screw nut 37 is then screwed to the bolt tip of the screw bolt 27, whereby the housing-side bolt passage 35 is clamped between the screw nut 37 and the bolt head 26. List of reference symbols 1 electrical machine housing 3, 5 housing parts 7 Front wall 9 Perimeter wall 11 Flange connection 13 Perimeter wall 15 Stator laminated core 17 Stator sleeve 18 coil winding 19 winding heads 21 Winding head space 23 Rotor shaft 25 storage location 26 Bolt head 27 screw bolts 28 Stator sleeve edge 29 connection point 31 Counter contour 33 bolt shaft 35 bolt passage 37 screw nut 39 groove-shaped recess 41 Groove bottom 43 groove flanks 44 headrest surface 45 flat sides 46 Opening edge area 47 narrow sides 49 reduced-section heel 51 Anti-twist profile a axial height t groove depth d measurement s match play m radial interference QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 114 748 A1

[0004] DE 10 2021 122 580 A1

[0004] FR 3 072 223 B1

[0004]

Claims

[1] Electric machine with an assembly formed from a stator sleeve (17) and a stator laminated core (15), in which the stator sleeve (17) is inserted into a hollow cylindrical electric machine housing (1) in a rotationally secure manner, characterized by that the stator sleeve (17) is extended in the axial direction by at least one securing element (27) which projects in particular beyond a front-side stator sleeve edge (28) with an axial height (a), and that the securing element (27) is in positive connection with a housing-side counter-contour (31), whereby a rotational lock of the stator sleeve (17) relative to the electric machine housing (1) is provided. [2] Electric machine according to claim 1, characterized bythat the securing element (27) is a component separate from the stator sleeve (17) which can be connected to the stator sleeve (17), and / or that the securing element (27) is a screw bolt which, in the assembled state, is in screw connection with its bolt shaft (33) to the electric machine housing (1). [3] Electric machine according to claim 2, characterized by that the bolt shank (33) of the screw bolt (27) projects through a cylindrical bolt passage (35) of the electric machine housing (1) and is in threaded engagement with its bolt tip with a screw nut (37) on the outside of the housing. [4] Electric machine according to claim 3, characterized bythat the stator sleeve (17) is deformable by pressing in the stator laminated core (15), whereby the positioning and / or alignment of the screw bolt (27) is subject to tolerances, and / or that in particular the screw bolt (27) is guided with hole play (s) through the housing-side bolt passage (35), and that in particular the hole play (s) is dimensioned sufficiently large to compensate for tolerances. [5] Electric machine according to one of claims 2 to 4, characterized by that the screw bolt (27) has a bolt head (26) which can be connected to the stator sleeve (17), and that in particular in the assembled state the housing-side bolt passage (35) is clamped between the screw nut (37) and the bolt head (26). [6] Electric machine according to claim 5, characterized bythat in the assembled state the bolt head (26) with its head support surface (44) is in axial pressure contact with an opening edge region (46) of the bolt passage (35), and / or that in particular during an assembly process the stator sleeve (17) with the stator laminated core (15) pressed into it can be inserted in the axial direction into the electric machine housing (1) until the head support surface (44) of the bolt head (26) comes into contact with the opening edge region (46) of the housing-side bolt passage (35). [7] Electric machine according to claim 6, characterized by that the bolt head (26) has on its head support surface (44) an anti-twist profile (51) which, in the assembled state, can be brought into material engagement with the opening edge region (46) of the housing-side bolt passage (35). [8] Electric machine according to one of claims 5 to 7, characterized bythat the bolt head (26) has an external thread which can be brought into threaded engagement with a nut thread of the stator sleeve (17), or that the bolt head (26) can be pressed in the axial direction into a recess (39) of the stator sleeve (17). [9] Electric machine according to claim 8, characterized by that the recess (39) of the stator sleeve (17) is a groove-shaped recess machined into the stator sleeve edge (28), and that the groove bottom (41) of the groove-shaped recess (39) is set back from the stator sleeve edge (28) by a groove depth (t). [10] Electric machine according to claim 9, characterized bythat the groove-shaped recess (39) is open radially inwards and radially outwards, so that only the groove flanks (43) of the groove-shaped recess (39) which are raised from the groove bottom (41) to the stator sleeve edge (28) can be brought into press fit with the bolt head (26), and / or that the bolt head (26) is flattened on its radially inner and outer sides (45) so that the bolt head (26) does not project radially beyond the groove-shaped recess (39) of the stator sleeve (17) or does so only with a slight excess, and / or that the bolt head (26), in particular on its narrow sides (47), has a knurling which can be brought into material engagement with the groove flanks (43) of the groove-shaped recess (39).

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