ELECTRIC MOTOR WITH PRINTED CIRCUIT BOARD

Abstract

An electric motor includes a first printed circuit board having layers with conductor tracks. The layers are spaced apart from one another by first layers of insulating material, for example, fiber-reinforced plastic, e.g., an epoxy material, and an insulating layer is arranged between two of the layers.

Claims

1-15. (canceled)

16. An electric motor, comprising: a first printed circuit board including layers having conductor tracks, the layers of the first printed circuit board being spaced apart from each other by first layers of insulating material, an insulating layer being arranged between two of the layers of the first printed circuit board.

17. The electric motor according to claim 16, wherein the insulating material includes a fiber-reinforced plastic and/or an epoxy material.

18. The electric motor according to claim 16, wherein a layer thickness of the insulating layer is greater than a layer thickness of the first layers.

19. The electric motor according to claim 16, wherein the insulating layer is made from a same material as the first layers.

20. The electric motor according to claim 19, wherein the first printed circuit board is arranged as a multilayered printed circuit board, the layers of the first printed circuit board being unevenly and/or irregularly spaced apart.

21. The electric motor according to claim 16, wherein the insulating layer is made of a different material than the first layers.

22. The electric motor according to claim 21, wherein the material of the insulating layer includes a plastic material.

23. The electric motor according to claim 22, wherein the plastic material includes enclosed gas bubbles and/or gas volumes.

24. The electric motor according to claim 16, further comprising: a stator housing accommodating a stator winding of the electric motor; a cover part; and a retaining ring arranged between the cover part and the stator housing and accommodating the first printed circuit board.

25. The electric motor according to claim 24, wherein the first printed circuit board and second printed circuit boards are arranged in a spatial region of the electric motor delimited and/or enclosed by the stator housing, the retaining ring, and the cover part.

26. The electric motor according to claim 25, wherein the first printed circuit boards and the second printed circuit boards are aligned parallel to one another and spaced apart from one another.

27. The electric motor according to claim 26, wherein an axis of rotation of a rotatably mounted rotor shaft of the electric motor is aligned parallel to a normal direction of the first printed circuit board.

28. The electric motor according to claim 25, wherein the second printed circuit boards are arranged on a side of the first printed circuit board facing away from the stator housing, and/or the first printed circuit board is arranged between the stator housing and the second printed circuit boards.

29. The electric motor according to claim 25, wherein a power module that is thermally conductively connected to the stator housing part is mounted on a side of the first printed circuit board that faces the stator housing.

30. The electric motor according to claim 29, wherein the power module and/or components mounted on the first printed circuit board on a side of the first printed circuit board facing the stator housing are operable up to a first temperature, the components mounted on the first printed circuit board on a side of the first printed circuit board facing away from the stator housing and components mounted on the second printed circuit boards are operable up to a second temperature, and the second temperature is lower than the first temperature.

31. The electric motor according to claim 30, wherein the first temperature is a maximum permissible operating temperature of the power module, the second temperature is a maximum permissible operating temperature of the components mounted on the first printed circuit board and the components mounted on the second circuit boards, and the second temperature is lower than the first temperature by at least 10° C.

32. The electric motor according to claim 25, wherein the second printed circuit boards are accommodated in the cover part.

33. The electric motor according to claim 25, wherein the first printed circuit board is connected to the second printed circuit board closest to the first printed circuit board by an electrical plug connection, each second printed circuit board being connected to a next closest second printed circuit board by a respective electrical plug connection.

34. The electric motor according to claim 24, wherein the retaining ring is formed of one piece or of several pieces.

35. The electric motor according to claim 24, wherein the retaining ring is sealed to the stator housing by an intermediate seal arranged as a thermal barrier, and/or the retaining ring is sealingly connected to the stator housing by an intermediate seal arranged as a thermal barrier.

36. The electric motor according to claim 25, wherein a fan is arranged in the spatial region and/or each of the second printed circuit boards has two axially continuous recesses arranged diametrically opposite one another with respect to an axis of rotation of a rotor shaft of the electric motor.

37. The electric motor according to claim 24, wherein the stator housing, the retaining ring, and the cover part are made of metal and/or as cast parts.

38. The electric motor according to claim 24, wherein an outer side of the cover part includes cooling ribs.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 is a schematic cross-sectional view of a first printed circuit board 40.

[0032] FIG. 2 is a schematic plan view of the first circuit board 40.

[0033] FIG. 3 is a schematic plan view of a first circuit board.

[0034] FIG. 4 is a cross-sectional view through an axial end region of an electric motor having a first circuit board 40.

[0035] FIG. 5 is a perspective, partial cross-sectional of the end region, associated with FIG. 4.

DETAILED DESCRIPTION

[0036] As shown in FIGS. 1, 2, 4, and 5, the printed circuit board 40 has a plurality of layers 1 with conductor tracks, the layers being spaced apart from one another by layers of insulating material 2, for example, fiber-reinforced plastic, e.g., an epoxy material.

[0037] An insulating layer 3 is applied between two of the layers, which, for example, is made of the same material as the layers, e.g., such that the printed circuit board 40 corresponds to a multilayered printed circuit board, whose layers 1 are not evenly spaced from one another. The material is therefore fiber-reinforced plastic, e.g., an epoxy material.

[0038] The insulating layer 3 is thicker, i.e., has a greater wall thickness, than the other layers.

[0039] Alternatively, the insulating layer 3 is made of a different material than the layers. A suitable material for the insulating layer 3 is a plastic that has enclosed gas bubbles, e.g., gas volumes.

[0040] In both configurations, the insulating layer 3 acts as a thermal barrier.

[0041] As shown in FIG. 2, the printed circuit board 40 has no vias in a central region 20, but only in an edge region 21 surrounding the central region 20. The vias arranged there are spaced irregularly from one another and impair the heat barrier effectiveness in the edge region.

[0042] Instead of the circular configuration of the printed circuit board illustrated in FIG. 2, a rectangular printed circuit board 40 can also be used, as shown in FIG. 3.

[0043] The circuit board is arranged in an electric motor. If the electric motor has a cuboid exterior shape, the circuit board of FIG. 3 is used.

[0044] As shown in FIG. 4, if the external shape of the electric motor is round, the printed circuit board 40 is configured according to FIG. 2.

[0045] The circuit board 40 is accommodated in a retaining ring 45 which is arranged between a stator housing 44 and a cover part 46 of the electric motor.

[0046] The stator of the electric motor is arranged inside the stator housing 44. On the B-side, on the stator housing 44, a spatial region for electronics is provided, which is surrounded by the stator housing 44, the retaining ring 45, and the cover part 46.

[0047] Second printed circuit boards 47, which are also provided with components, are also arranged in this space, together with the printed circuit board 40, which is the first printed circuit board.

[0048] The first printed circuit board 40 and the further printed circuit boards 47 are axially spaced apart and arranged parallel to one another.

[0049] The axial direction is parallel to the axis of rotation of the rotor shaft of the electric motor, which is arranged radially inside the stator.

[0050] The second printed circuit boards 47 are arranged on the side of the first printed circuit board 40 facing away from the stator housing 44.

[0051] The electronics include an inverter, whose controllable semiconductor switches are integrally arranged in a line module 42.

[0052] For cooling, the power module 42 is thermally conductively connected to the stator housing 44 on its side facing away from the first printed circuit board 40. The waste heat of the semiconductor switches, i.e., the power module, can thus be dissipated to the environment via the stator housing. However, the waste heat from the stator winding of the electric motor is also dissipated to the environment via the stator housing.

[0053] The power module is mounted on the circuit board 40. On the same side of the printed circuit board 40, e.g., the side facing the stator housing 44, further components 43 are mounted, which can be operated at a first temperature.

[0054] On the other side of the first printed circuit board 40 and the second printed circuit boards 47, components 41 are mounted, which can be operated up to a second temperature, which is however lower than the first temperature. The spatial region, i.e., these components, is cooled via the cover part 46.

[0055] The stator housing 44, the retaining ring 45, and the cover part 46 are each made of metal, e.g., as cast parts. The retaining ring 45 is sealingly connected both to the cover part 46 and to the stator housing part 44 by a respective intermediate seal.

[0056] The first circuit board 40 and the second circuit boards 47 are connected to their respective nearest neighbors by electrical connectors 48.

[0057] The second printed circuit boards 47 are spaced apart from one another by spacer bolts or spacer sleeves.

[0058] FIG. 5 is a perspective, partial cross-sectional view associated with FIG. 4.

[0059] The seals between the parts forming the housing, i.e., between the stator housing 44, the retaining ring 45, and the cover part 46, also act as a thermal barrier, as does the insulating layer 3 of the printed circuit board 40. Thus, the B-side end region is thermally isolated from the rest of the motor region.

[0060] The normal direction of the circuit board plane is parallel to the axis of rotation of the rotor shaft.

[0061] According to exemplary embodiments, the retaining ring 45 can be arranged in two pieces or in several pieces instead of in one piece, in which case the pieces are connected to one another in a sealed manner, e.g., by a respective seal.

[0062] According to exemplary embodiments, a fan is arranged within the spatial region. In this manner, air therein can be recirculated and thermal leveling can be achieved as a result.

[0063] For this purpose, the second circuit boards 47 have axially continuous recesses. These recesses are made sufficiently large so that the flow resistance is only insignificant. Each of the second printed circuit boards 47 has, for example, two recesses arranged diametrically opposite one another on the respective printed circuit board 47, so that ready circulation can be achieved.

LIST OF REFERENCE NUMERALS

[0064] 1 layer with conductor tracks [0065] 2 insulating material, for example, fiber-reinforced plastic, e.g., an epoxy material [0066] 3 insulating layer [0067] 20 central region [0068] 21 edge region with vias [0069] 40 first printed circuit board [0070] 41 first components [0071] 42 power module [0072] 43 second components [0073] 44 stator housing [0074] 45 retaining ring [0075] 46 cover part [0076] 47 second circuit board [0077] 48 plug connection [0078] 49 second temperature range [0079] 50 first temperature range