Structural concept of the prime mover for operation in the powertrain

Abstract

The present invention relates to a structural concept (1) of a prime mover for operation in the powertrain of a motor vehicle, characterized in that it comprises an electric motor (2) having a motor housing shell (6), a circuit board (7) having a control unit for controlling the electric motor (2), and an output shaft (9) of a transmission having a transmission housing shell (10), wherein a rotor shaft (5) of the electric motor (2) is arranged axially relative to the output shaft (9) of the transmission, the rotor shaft (5) of the electric motor (2) being rotatably supported in the output shaft (9) in the region of the transmission housing shell (10), the circuit board (7) being arranged between the electric motor (2) and the output shaft (9) of the transmission, and the rotor shaft (5) being guided through a recess (17) in the circuit board (7).

Description

[Technical Field]

[0001] The invention relates to a construction concept of a prime mover for operation in the powertrain of a motor vehicle according to the preamble of claim 1. [Background technology]

[0002] The non-smart solutions of the construction concept of a prime mover for operation in a powertrain known on the open market usually have the following components: - electric motors (DC, BLDC, SR = switched reluctance) for torques in the range of approximately 0.2 to 0.7 Nm, - reducers (worm gears or eccentric gears), - A rotor position sensor (for BLDC or SR motor types), typically implemented as a switched Hall sensor array.

[0003] "Smart prime movers" are often based on DC motors and often have an integrated sensor, typically implemented as a linear Hall sensor with a magnetic target, to detect the angle of the output shaft, but do not have a rotor position sensor, especially since DC motors do not in principle require one for operation.

[0004] The following requirements are imposed on the prime mover: - output torque ranging up to 25Nm, - Output angle range from approximately 20 to 120°; - self-locking or non-self-locking corresponding to the embodiment of the machine parts to be moved, - Availability of output shaft position information for safety, - Achieving positioning accuracy in the angular position of the output shaft.

[0005] A "dumb" prime mover must be operated or controlled externally, which requires additional controls, especially stand-alone controls, and additional electrical connections, such as a cable harness, for the motor's three-phase power supply.

[0006] The rotor position sensor needs to be powered and read out, which requires four or five additional electrical cables within the cable harness. Non-smart prime movers require additional components, specifically sensors or switches, for output shaft angle detection, as well as additional cable harnesses and plugs for powering and transmitting signals from the output shaft angle detection sensor.

[0007] Solutions based on DC motors are cheap, but they have self-locking and, moreover, the DC motor itself (unintended movement of the actuator due to a potential short circuit to earth) limits the fulfilment of safety requirements, especially ASIL-C, and only one angle sensor is required instead of two.

[0008] Solutions based on BLDC or SR motors have drawbacks regarding the integration and configuration of the rotor position and output shaft angle sensors, as the two sensors are typically located on opposite sides of the configuration, due, among other things, to the manufacturing method of the transmission, which prevents detection close to the axis of rotation, and requires the integration of a "sensor dome" outside the plane of the control unit's printed circuit board, which entails cost penalties.

[0009] In the case of a configuration based on a "smart" BLDC or SR motor, a typical actuator design, with the classical configuration of ECU (Electronic Control Unit)-motor transmission stage components, typically requires a larger radial manufacturing space for the circuit board compared to the diameter of the stator, resulting in a kind of mushroom head on one side of the stator and thus presenting drawbacks, especially with regard to the radial manufacturing space: classically, the circuit board implemented as a printed circuit board (= PCB) of the ECU is arranged axially on one side of the motor, and the projection of the PCB surface is typically larger than the diameter of the motor.

[0010] This may particularly affect adjacent components within the customer's designated manufacturing space, for example around the transmission or traction unit, or may affect the designated wiring such as hoses, pipes, cable harnesses and exhaust equipment that may also be required, thereby increasing the modification work required by the customer during installation.

[0011] In a typical configuration of PCB and electric motor, the Rotor Position Sensor System (RPS) is applied as follows: - a sensor magnet with a height of approximately 5 mm, - A gap of approximately 2 to 3 mm between the sensor and the IC. - Sensor IC with a height of approximately 2.5 mm. This configuration therefore has a very adverse effect on the axial manufacturing height of the actuator concept.

[0012] Typically, in actuators based on BLDC or SR motors, the rotor shaft is supported by rolling bearings on both sides (side A and side B). The output or connection to the pinion or gear is performed at the shaft end (side C), which is located opposite the PCB. This also negatively impacts the total manufacturing length of the concept.

[0013] Furthermore, this classical approach to the actuator concept requires a lid for shielding the printed circuit board as a further housing component, as well as an additional, separate environmental seal within the lid of the arrangement. Conventional ECU-motor-transmission construction concepts therefore require a relatively large manufacturing space, especially in terms of axial extent, and a relatively large number of individual components that must be further sealed from one another by additional, separate seals. Summary of the Invention [Problem to be solved by the invention]

[0014] The problem that the present invention aims to solve is therefore to provide a construction concept for a smart prime mover for operation in the powertrain of a motor vehicle, which improves over the prior art in terms of the required manufacturing space, the number of components and manufacturing costs. [Means for solving the problem]

[0015] This problem is solved according to the invention by a construction concept having the features of claim 1.

[0016] The structural concept according to the invention comprises an electric motor with a motor housing shell, a circuit board with a control unit for controlling the electric motor, and an output shaft of a transmission with a transmission housing shell, wherein the rotor shaft of the electric motor is arranged axially relative to the output shaft of the transmission, the rotor shaft of the electric motor being rotatably supported within the output shaft in the region of the transmission housing shell, the circuit board being arranged between the electric motor and the output shaft of the transmission, and the rotor shaft being guided through a recess in the circuit board.

[0017] The arrangement of the circuit board between the electric motor and the output shaft of the transmission leads to advantages, in particular with regard to the manufacturing space required, and also with regard to the material and manufacturing costs of the construction concept.

[0018] According to one embodiment, the circuit board is equipped with electronic components on both sides, with a first sensor for detecting the rotor position being arranged on the side of the circuit board facing the electric motor outside the cutout, and a second sensor for detecting the angle of the output shaft being arranged on the side of the circuit board facing the output shaft outside the cutout, thereby reducing the axial extent of the construction concept.

[0019] According to one embodiment, the first sensor is implemented as a magnetoresistive sensor or a switched Hall sensor array.

[0020] According to further embodiments, the second sensor is implemented as a linear Hall sensor, a single switched Hall sensor or a switched Hall sensor array.

[0021] According to one embodiment, a seal is further arranged between the motor housing shell and the transmission housing shell, said seal being embodied as a liquid seal or a solid seal, or alternatively, the seal can be injection molded into one of the two housing shells.

[0022] In particular, according to one embodiment, the radial extent of the motor housing shell essentially matches the radial extent of the electric motor, which contributes to a compact construction.

[0023] According to a further embodiment, the overall axial extent of the construction concept essentially corresponds to the sum of the axial extent of the motor housing shell and the axial extent of the transmission housing shell, which also contributes to a compact design.

[0024] According to one embodiment, the actuator is configured in a motor vehicle as a parking lock, an automatic transmission selector switch, a gear selector, or a clutch actuator.

[0025] According to one embodiment, the rotor shaft is furthermore rotatably supported in an output shaft, the bearing in the output shaft being embodied as a plain bearing or a rolling bearing.

[0026] In the following description, the features and details of the present invention will be explained by way of examples with reference to the accompanying drawings. Note that the features and relationships described in each variant can, in principle, be applied to all the embodiments. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a schematic diagram of a construction concept according to the prior art; [Figure 2] 1 is a schematic diagram of a construction concept according to the present invention; [Figure 3] 1 is a cross-sectional view of a prior art structural concept. [Figure 4] 1 is a cross-sectional view of a construction concept according to the present invention; [Figure 5] FIG. 1 is an exploded view of a construction concept according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] 1 shows a schematic diagram of a construction concept according to the prior art. A motor housing shell 6, which accommodates an electric motor 2, and a transmission housing shell 10, which essentially accommodates an output shaft 9, form the essential components of the housing of the construction concept. A seal 13 is arranged between the motor housing shell 6 and the transmission housing shell 10. A circuit board 7, in particular formed as a printed circuit board or PCB, on which a control unit 8, also called ECU, for controlling the electric motor 2 is arranged, is arranged on one side of the motor housing shell 6 opposite the output shaft 9 and is sealed from the space outside the housing by a further seal 13, which is arranged between the motor housing shell 6 and a lid 14.

[0029] Due to the fact that the projection of the printed circuit board surface is usually larger than the diameter of the electric motor 2, the prior art construction concept 1 has drawbacks, particularly with regard to the radial manufacturing space, since the radial extent of the motor housing shell 6 is necessarily larger than the radial extent of the electric motor 2. As a result, the motor housing shell 6 has a mushroom head shape.

[0030] FIG. 2 shows a schematic diagram of the structural concept according to the invention. A circuit board 7 with a control unit 8 for controlling the electric motor 2 is located here between the electric motor 2 in the motor housing shell 6 and the transmission output shaft 9 in the transmission housing shell 10. The radial manufacturing space of the motor housing shell 6 is therefore smaller than that of the prior art, since the radial extent of the motor housing shell 6 essentially matches that of the electric motor. A further advantage of the structural concept according to the invention is that only one seal 13 is required between the motor housing shell 6 and the transmission housing shell 10, since the motor housing shell 6 does not require a lid 14.

[0031] 1 and 2, the output shaft 9 exemplarily projects outside the transmission housing shell 10. In FIG.

[0032] Figure 3 shows a cross-section of a construction concept 1 according to 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. A transmission output shaft 9 is arranged in a transmission housing shell 10. In this case, the rotor shaft 5 of the electric motor 2 is axially aligned with the transmission output shaft 9. Furthermore, the rotor shaft 5 of the electric motor 2 is rotatably supported in the output shaft 9 in the region of the transmission housing shell 10.

[0033] The circuit board 7, printed circuit board or PCB, is located on one side of the motor housing shell 6 opposite the output shaft 9 and is sealed from the space outside the housing by a further seal 13 between the motor housing shell 6 and the lid 14.

[0034] The rotor position sensor system (RPS) is configured here as an axial extension of the rotor shaft 5. The sensor magnet is connected to one side of the rotor shaft 5 and is typically about 5 mm high. The sensor 11 itself is arranged on a printed circuit board and is typically about 2.5 mm high. The width of the air gap between the sensor magnet and the sensor 11 is typically about 2-3 mm. This configuration of the rotor position sensor system contributes to the axial manufacturing length of the construction concept. A further contribution to the axial manufacturing length comes from the lid that closes and seals the motor housing shell 6 in the area of ​​the circuit board 7.

[0035] FIG. 4 shows a cross-sectional view of the design concept according to the invention. The essential difference between this design concept and the design concept 1 shown in FIG. 3 according to the prior art, as already explained in the description of FIG. 2 and the schematic diagram of FIG. 1 according to the prior art, is that the circuit board 7 in FIG. 4 is arranged between the electric motor 2 and the output shaft 9 of the transmission. In FIG. 4, the circuit board 7 is arranged in the motor housing shell 6 at its edge relative to the transmission housing shell 10. However, the circuit board 7 can also be accommodated in the transmission housing shell 10, particularly at its edge relative to the motor housing shell 6. The rotor shaft 5 of the electric motor 2 is arranged axially relative to the output shaft 9 of the transmission and is rotatably supported in the output shaft 9 in the area of ​​the transmission housing shell 10. For this purpose, in the design concept 1 shown in FIG. 4, the rotor shaft 5 is guided through a corresponding recess 17 in the circuit board 7 and into the output shaft 9 in the transmission housing shell 10. At least one gear 18 of the transmission is arranged in the transmission housing shell 10.

[0036] A circuit board 7 having a control unit 8 for controlling the electric motor 2 is provided with electronic components on both sides.

[0037] In this case, a first sensor 11 for detecting the rotor position is arranged outside the recess 17 on the side of the circuit board 7 facing the electric motor 2, and thus "off-axis" with respect to the rotor shaft 5. The first sensor 11 is illustratively embodied as an MR or magnetoresistive sensor and may also be embodied as a switched Hall sensor array, typically having three Hall switching elements. A corresponding encoder is connected "off-axis" to the rotor shaft 5 so as to be non-rotatable relative to the rotor shaft 5.

[0038] A second sensor 12 for detecting the angle of the output shaft 9 is arranged on the side of the circuit board 7 facing the output shaft 9, outside the recess 17. The second sensor 12 may be embodied, for example, as a linear Hall sensor, a single switched Hall sensor or a switched Hall sensor array. A corresponding encoder is connected to the rotor shaft so that it cannot rotate relative to it.

[0039] Figure 5 shows an exploded view of the construction concept.

[0040] 4 and 5, the circuit board 7 is arranged between the electric motor 2 and the output shaft 9 of the transmission, so that the radial extent of the motor housing shell 6 essentially coincides with the radial extent of the electric motor 2.

[0041] Because the first sensor 11 for detecting the rotor position is not arranged on one side of the rotor shaft 5 as an axial extension of the rotor shaft 5, as in prior art sensors, but rather is arranged "off-axis", outside the cutout 17 in the circuit board, i.e. outside the rotor shaft 5, and because the cover 14 can be omitted, the overall axial extent of the structural concept essentially corresponds to the sum of the axial extent of the motor housing shell 6 and the axial extent of the transmission housing shell 10.

[0042] Further substantial advantages of the structural concept 1 according to the present invention over the structural concept 1 according to the prior art relate in particular to the reduction of material and manufacturing costs, since the second seal 13 arranged between the lid 14 and the motor housing shell 6, the lid 14 itself and the steps involved in their manufacture can be saved.

[0043] Furthermore, both sensors 11, 12 can be assembled as SMD components using reflow techniques when attaching the parts to the printed circuit board 7, meaning that a sensor dome is not required to detect rotating components.

[0044] In particular, here a plug 16 is arranged in the motor housing shell 6, in particular for signal transmission. [Explanation of symbols]

[0045] 1. Structural concept 2 electric motors 3 Stator 4 rotors 5 rotor shaft 6 Motor housing shell 7 Circuit Board 8 Control unit, electronic components 9 Transmission output shaft 10 Transmission housing shell 11 First sensor 12 Second sensor 13 Seal 14 Lid 15 Bearings 16 Plug 17 Circuit board cutout 18 Gears inside the transmission housing shell

Claims

1. A prime mover arrangement (1) for operation in the powertrain of a motor vehicle, comprising: an electric motor (2) having a motor housing shell (6); a circuit board (7) having a control unit (8) for controlling said electric motor (2); a transmission output shaft (9) having a transmission housing shell (10); a rotor shaft (5) of the electric motor (2) is arranged axially relative to the output shaft (9) of the transmission, and the rotor shaft (5) of the electric motor (2) is rotatably supported in the output shaft (9) within the transmission housing shell (10); the circuit board (7) is arranged between the electric motor (2) and the output shaft (9) of the transmission, and the rotor shaft (5) is guided through a notch (17) in the circuit board (7); Both sides of the circuit board (7) are equipped with electronic components, a first sensor (11) for detecting the rotor position is arranged outside the notch (17) on the side of the circuit board (7) facing the electric motor (2), and a second sensor (12) for detecting the angle of the output shaft (9) is arranged outside the notch (17) on the side of the circuit board (7) facing the output shaft (9), i.e., arranged off-axis with respect to the rotor shaft (5) and the output shaft (9); the transmission is arranged asymmetrically with respect to the axes of the rotor shaft (5) and the output shaft (9); Structure (1).

2. characterised in that the first sensor (11) is implemented as a magnetoresistive sensor or a switched Hall sensor array, A structure (1) according to claim 1.

3. the second sensor (12) is implemented as a linear Hall sensor, a single switched Hall sensor or a switched Hall sensor array; A structure (1) according to claim 1 or 2.

4. A seal (13) is disposed between the motor housing shell (6) and the transmission housing shell (10). A structure (1) according to any one of claims 1 to 3.

5. the seal (13) is embodied as a liquid or solid seal or is formed by injection into one of the two housing shells, 5. The structure (1) according to claim 4.

6. the motor housing shell (6) is radially intimately attached to the electric motor (2), A structure (1) according to any one of claims 1 to 5.

7. the axial extent of the structure excluding the output shaft (9) corresponds to the sum of the axial extent of the motor housing shell (6) and the axial extent of the transmission housing shell (10), A structure (1) according to any one of claims 1 to 6.

8. The prime mover is configured in a motor vehicle as a parking lock, an automatic transmission selector switch, a gear selector, or a clutch actuator. A structure (1) according to any one of claims 1 to 7.

9. the rotor shaft (5) is rotatably supported in the output shaft (9), and a bearing (15) in the output shaft (9) can be implemented as a plain bearing or a rolling bearing. A structure (1) according to any one of claims 1 to 8.

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