ELECTRIC MACHINE STAR DISC

Abstract

A star disc, for a rotor of an electric machine, comprising a plurality of pole arms configured to wind a wire around a winding; a switching ring having protruding contacts, the switching ring being held in a rotationally fixed manner in a recess of the star disc; and an external plastic overmolding structured to hold the switching ring to the star disc in an axially form-fitting manner.

Claims

1. A star disc, for a rotor of an electric machine, comprising: a plurality of pole arms configured to wind a wire around a winding; a switching ring having protruding contacts, the switching ring being held in a rotationally fixed manner in a recess of the star disc; and an external plastic overmolding structured to hold the switching ring to the star disc in an axially form-fitting manner.

2. The star disc according to claim 1, wherein the switching ring is an injection molding switching ring with one or more bridges embedded in plastic.

3. The star disc according to claim 1, wherein the star disc has a base body that forms the plurality of pole arms which are star-shaped.

4. The star disc according to claim 1, wherein the external plastic overmolding has a section overlapping the switching ring as a cover, ring, or tab.

5. The star disc according to claim 1, wherein the switching ring has a geometry including recesses and elevations extending in an axial direction and projections and recesses extending in a radial direction such that predetermined sections of the switching ring are partially or completely covered by parts of the external plastic overmolding.

6. The star disc according to claim 1, further comprising a form fit and optionally a material fit with the external plastic overmolding on an outer side of the switching ring.

7. The star disc according to claim 3, wherein the switching ring is centred in a receptacle on an outer side of the base body.

8. An electric machine comprising: a rotor having a star disc comprising a plurality of pole arms configured to wind a wire around a winding; a switching ring having protruding contacts, the switching ring being held in a rotationally fixed manner in a recess of the star disc; and an external plastic overmolding structured to hold the switching ring to the star disc in an axially form-fitting manner; and a stator that co-operates with the rotor during operation.

9. The electric machine according to claim 8, wherein the switching ring is an injection molding switching ring with one or more bridges embedded in plastic.

10. The electric machine according to claim 8, wherein the star disc has a base body that forms the plurality of pole arms that are star-shaped.

11. The electric machine according to claim 8, wherein the external plastic overmolding has a section overlapping the switching ring as a cover, ring, or tab.

12. The electric machine according to claim 8, wherein the switching ring has a geometry including recesses and elevations extending in an axial direction and projections and recesses extending in a radial direction such that predetermined sections of the switching ring are partially or completely covered by parts of the external plastic overmolding.

13. The electric machine according to claim 8, further comprising a form fit and optionally a material fit with the external plastic overmolding on an outer side of the switching ring.

14. The electric machine according to claim 10, wherein the switching ring is centred in a receptacle on an outer side of the base body.

15. The electric machine according to claim 8, wherein the electric machine is a motor.

16. A method for producing a star disc, the method comprising: (a) providing a star disc base body having a plurality of pole arms configured to wind a wire around a winding; (b) placing a switching ring, having protruding contacts that project axially, on the star disc base body; and (c) applying a plastic overmolding over a surface of the star disc base body and over at least a portion of the switching ring such that the switching ring is fixed to the star disc base body in an axial direction.

17. The method according to claim 16, further comprising producing the switching ring by injection molding prior to step (a).

18. The method according to claim 16, wherein a positions and/or orientation of the star disc base body and of the switching ring are determined by a tool.

19. The method according to any one of claim 16, wherein the star disc base body is preheated.

20. The method according to claim 16, wherein the switching ring is filled with a branch channel filling.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 is an exploded view of the star disc according to the disclosure,

[0033] FIG. 2 is a longitudinal sectional view of the star disc in the manufactured state according to the disclosure,

[0034] FIG. 3 shows the star disc in a perspective front view with a plastic overmolding,

[0035] FIG. 4 shows the star disc in a perspective front view without a plastic overmolding,

[0036] FIG. 5 shows the star disc in a perspective rear view without a plastic overmolding,

[0037] FIG. 6 shows the switching ring in a front view,

[0038] FIG. 7 shows the switching ring in a perspective rear view, and

[0039] FIGS. 8A-8C are perspective views of various bridges.

DETAILED DESCRIPTION

[0040] The figures are schematic in nature and are intended solely to aid understanding of the disclosure. The same elements are labelled with the same reference signs. Features of the individual embodiments can be exchanged among one another and used alternatively or cumulatively.

[0041] FIG. 1 shows the star disc (1) for a rotor of an electric machine (not shown), the star disc (1) having pole arms (2) that are intended to be wound with wire of a winding, with a switching ring (3), from which contacts (4), i.e., contacts for making contact with the wire of the winding, project axially, the switching ring (3) being held in a rotationally fixed manner in a recess (5), or centring recess, or centring diameter of the star disc (1). It should be emphasised that the star disc (1) has a plastic overmolding (6) on the outside, which fixes the switching ring (3) to the star disc (1) in an axially positive manner in the axial direction (7), or retains it, or fastens it.

[0042] FIG. 1 shows an exploded view of the star disc in a schematic view.

[0043] To provide better clarity, a radial direction (8) and a circumferential direction (9) are defined in addition to an axial direction (7). The axial direction (7) extends in the direction of a centre axis (10) of the star disc (1). The radial direction (8) is aligned perpendicularly to the axial direction (7). The circumferential direction (9) describes the direction of rotation of the rotor in which the star disc (1) is arranged.

[0044] The star disc (1) has a star disc base body (11) on one side. This star disc base body (11) in turn has an annular base body (12), which has pole arms (2) distributed in the circumferential direction (9), arranged evenly in relation to one another and projecting outwards in the radial direction (8). A total of six pole arms (2) are shown in the present diagram, whereby a pole arm (2) follows every 60 in the circumferential direction (9).

[0045] Each pole arm (2) has a head section (13) that extends in a radial direction (8) and is plate-shaped on the pole arms (2). The head section (13) and the pole arms (2) are of anchor-shaped cross-section. The ring-shaped base body of the star disc base body (12) has, axially on the front side, a recess (5) in the form of an annular step or notch extending in the axial direction (7), in which the switching ring (3) is positioned.

[0046] The switching ring (3), arranged on the front side of the star disc base body (11), has a base body (15) made of plastic, which is provided by a plastic overmolding, from which contacts (4) project on the front side in the axial direction (7). The contacts (4) are formed on a bridge (47), with three embodiments being shown in FIGS. 8a, 8b, and 8c in a perspective view.

[0047] On the front side of the switching ring (3), a total of six contacts (4) are arranged in the circumferential direction (9) at equal distances from one to another. The contacts (4) can be designed in the form of blocks. They are shown in purely schematic form and other designs are conceivable. The contacts (4) are made of a material separate from the plastic.

[0048] The plastic overmolding (6) is positioned in the axial direction (7) at the front side of the star disc base body (11). The plastic overmolding (6) has a similar design to the star disc base body (11). The plastic overmolding (6) has an annular base body (17), which has pole arms (18) that are distributed in the circumferential direction (9), aligned uniformly with one to the other and extend outwards in the radial direction (8). In FIG. 1, a total of six pole arms (18) are shown, whereby a pole arm (18) is arranged in the circumferential direction every 60. Each pole arm (18) has a head section (19), which is plate-shaped in the radial direction (8) on the pole arms (18). The head section (19) and the pole arms (18) are anchor-shaped in cross-section. There are, of course, as many pole arms (2) as there are pole arms (18).

[0049] The plastic overmolding (6) is designed to rest with its back side at least partially against a surface (20) of the front side of the switching ring (3) (see FIG. 4) and a surface (21) of the front side of the star disc base body (11).

[0050] In FIG. 2, a sectional view of the star disc (1) is shown in the assembled state. The switching ring (3) is positioned in the recess (5). The switching ring (3) has an annular counter-step (22) on the axial rear side that matches the step forming the recess (5), which is formed further out on the switching ring (3) and passes through an outer side (23) of the switching ring (3) on the circumference. The counter-step (22) is designed in the form of a bevel or step. The switching ring (3) thus has two levels (24, 25).

[0051] The first level (24) of the switching ring (3) hereby relates to the part of the switching ring (3) which is positioned in the recess (5). The second level (25) of the switching ring (3) describes how the switching ring (3) rests against the frontal surface (21) of the star disc base body (11).

[0052] The plastic overmolding (6) lies against the switching ring (3) and the star disc base body (11). The plastic overmolding (6) is designed in such a way that it rests against the free outer side (23) of the switching ring (3), which is not covered by an inner side (26) of the recess (5) of the star disc base body (11). The ring-shaped base body (17) of the plastic overmolding (6) lies radially on the inside, with its inner side or inner wall or inner lateral surface (27) at least partially on the free outer wall, or outer lateral surface, or outer side (23) of the switching ring (3), and holds the switching ring (3) in a form-fitting manner on the star disc base body (11). The plastic overmolding (6) extends in the axial direction (7) beyond the switching ring (3).

[0053] In FIG. 3, a specific design of the star disc (1) with an arranged switching ring (3) and plastic overmolding (6) is shown.

[0054] The switching ring (3) has, on the front side, recesses (28) and raised portions (29, 30, 31), which run in sections in the circumferential direction (9) and are formed in the axial direction (7). These recesses (28) and raised portions (29, 30, 31) are formed on the second plane 25 of the switching ring (3). The recesses (28) and raised portions (29, 30, 31) alternate circumferentially (9) with each other in an alternating manner.

[0055] In the present design, a total of three recesses (28) and three elevations (29, 30, 31) are configured. In the sections of the elevations (29, 30, 31), the contacts (4) are arranged.

[0056] In the circumferential direction (9) between an elevation (29, 30, 31) and a recess (28), a step (32) is shaped which forms a transition from the elevation (29, 30, 31) to the recess (28) and replace from the recess (28) to the elevation (29, 30, 31). Three directly adjacent steps (32) in the peripheral direction (9) each form a centering geometry of the switching ring (3) in an injection moulding tool that facilitates the production of the plastic overmolding (6).

[0057] A branch channel (33) is formed in the elevations (29, 30, 31) from radially outwards to radially inwards. The branch channel (33) has a straight extension in the radial direction (8) and a rectangular cross-section. The branch channel (33) is limited to penetrating the outer side (23), while the branch channel (33) does not penetrate the inner side or inner wall (34) of the switching ring (3). The branch channel serves not only to encase and reinforce the plastic overmolding, but also to ensure that the bridges are correctly positioned in the plastic overmolding process of the switching ring. The inner side (34) of the switching ring (3) has three to six recesses to ensure that the plastic overmolding process of the switching ring (3) is carried out correctly.

[0058] On the outer side (23), at the position of elevation (29, 30, 31), a radially inwardly extending arcuate or semi-circular first indentation or first recess (35) is formed with a radius, which is aligned symmetrically to the branch channel (33) in the circumferential direction (9). The first recesses (35) penetrate the outer side (23) of the switching ring (3).

[0059] In the recesses (28), there are also a second indentation or second recess (36), which is curved or semi-circular and extends radially inwards, with a radius. The second recesses (36) penetrate the outer side (23) of the switching ring (3).

[0060] The switching ring (3) has two first projections (38) extending in the radial direction (8). The projections (38) are aligned at 180 to one another in the circumferential direction (9). The projections (38) are formed partly on an elevation (29, 30) and partly on a recess (28) in the radial direction (8). A contact (4) is positioned on that section of the projection (38) of the elevation (29, 30).

[0061] The design of the plastic overmolding (6) is made from the axial direction (7) according to a cover (39). The second level 25 of the switching ring (3) is embedded in the plastic overmolding (6) on the circumference. The above-described branch channels (33) are filled with the plastic overmolding (6). The recesses (35, 36) are filled in a contour-shaped manner, that is not fully voluminous in the radial direction (8). In the plastic overmolding, (6) apertures or free spaces (40) are formed in a circular shape. This means that one area is free of plastic overmolding (6). In accordance with the circular shape of the free spaces (40) and the arrangement of these, the contour-shaped filling of the first and second recesses (35, 36) is formed by the contour of the free spaces (40) in the plastic overmolding (6). The plastic overmolding (6) is designed to be flat at the front in relation to the recesses (28) and elevations (29, 30, 31).

[0062] The pole arms (2) and the head sections (13) of the star disc base body (11) are covered on the surface side with the plastic overmolding (6).

[0063] FIG. 4 shows the star disc (1) with a switching ring (3) without a plastic overmolding (6). FIG. 4 shows further recesses (41) that were previously hidden by the plastic overmolding (6). The switching ring (3) has further recesses (41, 42) and projections (43) in addition to the first projections (38) and first and second recesses (35, 36) described above. On the radially outer side of the switching ring (3), in the sections of the raised portions (29, 30, 31), there are formed partial sections with third recesses (41), which extend in sections in the circumferential direction (9). At the same time, a second projection (43) is formed in these partial sections, which extends in sections in the circumferential direction (9). Further, fourth recesses (42) are formed on the first projections (38) in the circumferential direction (9) towards the adjacent branch channel (33).

[0064] A single view of the switching ring (3) according to an equal perspective is shown in FIG. 6.

[0065] FIG. 5 shows a rear view of the star disc (1) according to FIG. 4 on the star disc base body (11). The star disc base body (1) has a planar rear side surface. The star disc base body (11) has a single axial through-hole (44) on the ring-shaped base body of the star disc base body (12), with an anti-rotation projection (45) partially entering the through-hole (44) in the axial direction (7). The anti-rotation projection (45) is formed on the rear side of the switching ring (3). The contour of the anti-rotation projection (45) is star-shaped.

[0066] FIG. 7 shows a rear view of the switching ring 3. In FIG. 7, the switching ring (3) is shown in a perspective rear view. In FIG. 7, the complete design of the two levels (24, 25) of the switching ring (3) can be seen. The previously described projections (38, 43) are formed on the second level (25) and extend in sections in the radial direction (8) along the circumferential direction (9). FIG. 7 clearly shows that the first projections (38) extend further in the radial direction (8) than the second projections (43). The first projections (38) and second projections (43) have an underside (46) that is intended to rest against the surface (21) of the star disc base body (11), namely, the surface of the ring-shaped base body of the star disc base body (12). The anti-rotation projection (45), which has already been described, is also shown in FIG. 7. The first level (24) of the switching ring (3) is designed to be ring-shaped and constant in the circumferential direction (9).

[0067] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0068] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

REFERENCE DESIGNATION LIST

[0069] 1 Star disc [0070] 2 Pole arm [0071] 3 Switching ring [0072] 4 Contact [0073] 5 Recess [0074] 6 Plastic overmolding [0075] 7 Axial direction [0076] 8 Radial direction [0077] 9 Circumferential direction [0078] 10 Center axis [0079] 11 Star disc base body [0080] 12 Base body of the star disc base body [0081] 13 Head section [0082] 15 Base body of the switching ring [0083] 17 Base body of the plastic overmolding [0084] 18 Pole arm of the plastic overmolding [0085] 19 Head section of the plastic overmolding [0086] 20 Surface of the switching ring [0087] 21 Surface of the star disc base body [0088] 22 Counter-step [0089] 23 Outer side of the switching ring [0090] 24 First level of the switching ring [0091] 25 Second level of the switching ring [0092] 26 Inner side of the recess of the star disc base body [0093] 27 Inner side of the plastic overmolding [0094] 28 First recess [0095] 29 First elevation [0096] 30 Second elevation [0097] 31 Third elevation [0098] 32 Step [0099] 33 Branch channel [0100] 34 Inner side [0101] 35 First recess [0102] 36 Second recess [0103] 38 First projection [0104] 39 Cover [0105] 40 Free space [0106] 41 Third recess [0107] 42 Fourth recess [0108] 43 Second projection [0109] 44 Through-hole [0110] 45 Anti-rotation projection [0111] 46 Underside [0112] 47 Bridge