DESIGN CONCEPT OF A DRIVE FOR ACTUATION IN THE DRIVE TRAIN

Abstract

A structural concept of a drive for an actuation device in a drive train of a motor vehicle, contains an electric motor with a motor housing shell, a circuit carrier with a control unit for controlling the electric motor, and an output shaft of a gearbox with a gearbox housing shell. The rotor shaft of the electric motor is arranged axially with respect to the output shaft of the gearbox, and the rotor shaft of the electric motor is accommodated in the output shaft in a rotatably mounted manner in the region of the gearbox housing shell. The circuit carrier is arranged between the electric motor and the output shaft of the gearbox, and the rotor shaft leads through a cutout in the circuit carrier.

Claims

1-10. (canceled)

11. A structural concept of a drive for an actuator in a drive train of a motor vehicle, the structural concept comprising: an electric motor with a motor housing shell and a rotor shaft; a circuit carrier with a controller for controlling said electric motor; a gearbox having an output shaft and a gearbox housing shell, said rotor shaft of said electric motor being disposed axially with respect to said output shaft of said gearbox, and said rotor shaft of said electric motor being accommodated in said output shaft in a rotatably mounted manner in a region of said gearbox housing shell; and said circuit carrier disposed between said electric motor and said output shaft of said gearbox, said circuit carrier having a cutout formed therein and said rotor shaft leading through said cutout in said circuit carrier.

12. The structural concept according to claim 11, wherein said circuit carrier is equipped with electronic components on both sides, said electronic components include a first sensor for detecting a rotor position and is disposed outside said cutout on a side of said circuit carrier facing said electric motor, and a second sensor for detecting an angle of said output shaft and is disposed outside said cutout on a side of said circuit carrier facing said output shaft.

13. The structural concept according to claim 12, wherein said first sensor is a magnetoresistive sensor or as a switched Hall sensor array.

14. The structural concept according to claim 12, wherein said second sensor is a linear Hall sensor, a single-switched Hall sensor or a switched Hall sensor array.

15. The structural concept according to claim 11, further comprising a seal disposed between said motor housing shell and said gearbox housing shell.

16. The structural concept according to claim 15, wherein said seal is a liquid seal or a solid seal or is injection-molded onto one of said motor housing shell or said gearbox housing shell.

17. The structural concept according to claim 11, wherein that a radial extension of said motor housing shell corresponds substantially to a radial extension of said electric motor.

18. The structural concept according to claim 11, wherein a total axial extension of the structural concept corresponds substantially to a sum of an axial extension of said motor housing shell and an axial extension of said gearbox housing shell.

19. The structural concept according to claim 11, wherein the actuator is configured as a parking lock, as an automatic transmission selector switch, as a gear selector or as a clutch actuator in the motor vehicle.

20. The structural concept according to claim 11, wherein said output shaft has a bearing, said rotor shaft is mounted rotatably in said output shaft, it being possible for said bearing in said output shaft to be a sliding bearing or a rolling body bearing.

Description

[0035] The features and details of the invention are explained in greater detail in the following description in conjunction with the accompanying drawings with reference to exemplary embodiments. In this case, features and relationships described in individual variants can in principle be applied to all exemplary embodiments. In the drawings:

[0036] FIG. 1 shows a schematic representation of a structural concept from the prior art,

[0037] FIG. 2 shows a schematic representation of a structural concept according to the invention,

[0038] FIG. 3 shows a section through a structural concept from the prior art.

[0039] FIG. 4 shows a section through a structural concept according to the invention

[0040] FIG. 5 shows an exploded view of the structural concept.

[0041] FIG. 1 shows a schematic representation of a structural concept from the prior art. A motor housing shell 6, which accommodates the electric motor 2, and a gearbox housing shell 10, which substantially accommodates the output shaft 9, form the essential components of the housing of the structural concept. A seal 13 is arranged between the motor housing shell 6 and the gearbox housing shell 10. A circuit carrier 7, in particular in the form of a printed circuit board or PCB, on which a control unit 8, also referred to as an ECU, for controlling the electric motor 2 is arranged, is arranged frontally on the side of the motor housing shell 6 facing away from the output shaft 9, and is sealed off from the space outside the housing by means of a further seal 13 between the motor housing shell 6 and a cover 14.

[0042] By virtue of the fact that the projection of the surface of the printed circuit board is generally larger than the diameter of the electric motor 2, this structural concept 1 from the prior art has in particular the disadvantage with respect to the installation space in the radial direction, since here the radial extension of the motor housing shell 6 is necessarily larger than the radial extension of the electric motor 2. As a result, the motor housing shell 6 assumes the shape of a mushroom head.

[0043] FIG. 2 shows a schematic representation of the structural concept according to the invention. The circuit carrier 7 with a control unit 8 for controlling the electric motor 2 is arranged here between the electric motor 2 in the motor housing shell 6 and the output shaft 9 of the gearbox in the gearbox housing shell 10. The installation space of the motor housing shell 6 in the radial direction is thus smaller than in the prior art, since the radial extension of the motor housing shell 6 now corresponds substantially to the radial extension of the electric motor 2. A further advantage of this structural concept 1 is that only a single seal 13 is required here, specifically between the motor housing shell 6 and the gearbox housing shell 10, since the motor housing shell 6 does not require a cover 14.

[0044] In FIG. 1 and in FIG. 2, for example, the output shaft 9 projects out of the gearbox housing shell 10.

[0045] FIG. 3 shows a section through a structural concept 1 from the prior art. An electric motor 2 is arranged in a motor housing shell 6. The electric motor 2 comprises a stator 3 and a rotor 4 with a rotor shaft 5. An output shaft 9 of a gearbox is arranged in a gearbox housing shell 10. In this case, the rotor shaft 5 of the electric motor 2 is aligned axially with respect to the output shaft 9 of the gearbox. Furthermore, the rotor shaft 5 of the electric motor 2 is accommodated in the output shaft 9 in a rotatably mounted manner in the region of the gearbox housing shell 10.

[0046] A circuit carrier 7 or printed circuit board or also PCB is arranged frontally on the side of the motor housing shell 6 facing away from the output shaft 9 and is sealed off from the space outside the housing by means of a further seal 13 between the motor housing shell 6 and a cover 14.

[0047] A rotor position sensor system (RPS) is configured here axially as a continuation of the rotor shaft 5. The sensor magnet is connected to the corresponding end face of the rotor shaft 5 and is generally about 5 mm high. The sensor 11 itself is arranged on the printed circuit board and is generally about 2.5 mm high. The air gap between the sensor magnet and the sensor 11 is generally of the order of magnitude of approximately 2-3 mm. This arrangement of the rotor position sensor system contributes to the axial structural length of the structural concept. A further contribution to the axial structural length is made by the cover for closing and sealing the motor housing shell 6 in the region of the circuit carrier 7.

[0048] FIG. 4 shows a section through the structural concept according to the invention. The essential difference between this structural concept and the structural concept 1 from FIG. 3 from the prior art is, as already explained in the discussion of the schematic representations of FIG. 2 and FIG. 1, in which FIG. 1 shows prior art, that the circuit carrier 7 in FIG. 4 is arranged between the electric motor 2 and the output shaft 9 of the gearbox. In FIG. 4, the circuit carrier 7 is located in the motor housing shell 6 in the edge region towards the gearbox housing shell 10, but it would also be possible to accommodate the circuit carrier 7 in the gearbox housing shell 10, in particular in the edge region towards the motor housing shell 6. The rotor shaft 5 of the electric motor 2 is arranged axially with respect to the output shaft 9 of the gearbox, and here it is accommodated in the output shaft 9 in a rotatably mounted manner in the region of the gearbox housing shell 10. In this structural concept 1 in FIG. 4, the rotor shaft 5 is guided for this purpose through a corresponding cutout 17 in the circuit carrier 7 into the gearbox housing shell 10 to the output shaft 9. At least one toothed wheel 18 of the gearbox is also arranged in the gearbox housing shell 10.

[0049] The circuit carrier 7, with a control unit 8 for controlling the electric motor 2, is equipped on both sides with electronic components.

[0050] In this case, a first sensor 11 for detecting the rotor position is arranged outside the cutout 17, and thus “off-axis” with respect to the rotor shaft 5, that is outside the rotor shaft 5, on the side of the circuit carrier 7 facing the electric motor 2. The first sensor 11 is realized, for example, as an MR sensor or magnetoresistive sensor, but can also be realized as a switched Hall sensor array, with typically three Hall switching elements. A corresponding encoder is connected to the rotor shaft 5 in a rotationally fixed manner correspondingly “off-axis”.

[0051] A second sensor 12 for detecting the angle of the output shaft 9 is arranged outside the cutout 17 on the side of the circuit carrier 7 facing the output shaft 9. The second sensor 12 can be realized, for example, as a linear Hall sensor, as a single-switched Hall sensor or as a switched Hall sensor array. A corresponding encoder is connected to the output shaft in a rotationally fixed manner.

[0052] FIG. 5 shows an exploded view of the structural concept.

[0053] By virtue of the fact that the circuit carrier 7 in FIG. 4 and FIG. 5 is arranged between the electric motor 2 and the output shaft 9 of the gearbox, the radial extension of the motor housing shell 6 here corresponds substantially to the radial extension of the electric motor 2.

[0054] By virtue of the fact that the first sensor 11 for detecting the rotor position is arranged not like in the prior art axially as a continuation of the rotor shaft 5 on the end face thereof but “off-axis” outside the cutout 17 in the printed circuit board and thus outside the rotor shaft 5, and by virtue of the fact that the cover 14 can be omitted, the entire axial extension of the structural concept corresponds substantially to the sum of the axial extensions of the motor housing shell 6 and the axial extension of the gearbox housing shell 10.

[0055] A further significant advantage of the structural concept 1 according to the invention over the structural concept 1 according to the prior art relates to the lower material costs and the production costs, since in particular the second seal 13 between the cover 14 and the motor housing shell 6 and also the cover 14 itself, and the production steps associated therewith, can be dispensed with.

[0056] Furthermore, both sensors 11, 12 can be assembled as SMD components in the ReFlow process when equipping the printed circuit board 7, that is no sensor domes are required for sensing the rotating components.

[0057] In particular, a connector 16 is arranged here on the motor housing shell 6, in particular for transmitting signals.

LIST OF REFERENCES DESIGNATIONS

[0058] 1 Structural concept, [0059] 2 Electric motor, [0060] 3 Stator, [0061] 4 Rotor, [0062] 5 Rotor shaft, [0063] 6 Motor housing shell, [0064] 7 Circuit carrier, [0065] 8 Control unit, electronic components [0066] 9 Output shaft of a gearbox, [0067] 10 Gearbox housing shell, [0068] 11 First sensor, [0069] 12 Second sensor, [0070] 13 Seal, [0071] 14 Cover, [0072] 15 Bearing, [0073] 16 Connector, [0074] 17 Cutout in the circuit carrier, [0075] 18 Toothed wheel in the gearbox housing shell