Motor unit

Abstract

The invention relates to a motor unit, comprising an electric motor and a converter for supplying power to the electric motor, wherein the electric motor comprises a motor housing, out of which connection cables lead, and the converter comprises a housing lower part, on which a power connection is arranged, coupling points to which the connection cables can be connected in a current-conducting manner being provided on the power connection. The invention proposes arranging a carrier between the electric motor and the converter, the carrier comprising a carrier part and a carrier part cover, which enclose a connection space in which the coupling points are arranged.

Description

[0001] Motor unit

[0002] The invention relates to a motor unit comprising an electric motor and a converter for supplying power to the electric motor. The motor unit is suitable for installation in a motor vehicle drive train.

[0003] Such a converter, also known as a power converter or inverter, provides the voltage required to operate an electric motor, for example, in a motor vehicle's drive system. The converter has a metal housing, usually with a lower and an upper section, which can usually be hermetically sealed and in which one or more required power electronics components, such as one or more power modules, also known as IGBTs, are housed.

[0004] To cool the IGBT modules, a cooling device is provided on the housing side, which essentially cools the IGBT modules of the converter, which can be integrated into a cooling medium circuit so that heat loss generated during operation can be dissipated via the coolant.

[0005] Such a converter or inverter system is known from DE 10 2020 121 917 A1. This discloses a multi-part housing comprising an electronics level, a power level, and a connection level. The interior of the housing has several zones in which different conditions prevail with regard to temperature and / or EMC shielding. A cooling device is provided for temperature control, which can be connected to a cooling circuit.

[0006] A motor unit with an inverter is known from WO 19208069 A1. The proposed motor unit comprises a motor with a motor housing and an inverter with an inverter housing. It is proposed to provide a motor unit in which the inverter housing and the motor housing are fixed to each other, the connection being made by means of bolts. The electrical connection between the inverter unit and the motor is established via a motor connection terminal with three busbars. The busbars, or inverter output busbars, protrude from the inverter housing so that they can be inserted into an opening in the motor housing. The busbars, which are supported by the motor connection terminal, can be electrically connected to the motor within the motor housing.

[0007] A motor connection terminal is also known from WO 19208445 A1. The motor connection terminal comprises a plug-in connection consisting of two connectors, with the busbars being routed through one connector. The busbars are designed to extend through the openings in the motor housing and the converter housing into the respective housings, allowing the busbar to be electrically connected to the motor and converter there by means of a screw connection. The plug-in connection is also designed to align the motor housing and converter housing with each other.

[0008] This design requires that the wiring elements and busbar be able to accommodate elastic deformation. To mount the converter to the motor, the motor housing must have an opening with a cover through which the screw connection can be made.

[0009] The object of the invention is to propose a motor unit that provides an improved solution for the connection between motor and inverter.

[0010] The object is achieved according to the invention by an embodiment according to the independent claim. Further advantageous embodiments of the present invention can be found in the subclaims.

[0011] A motor unit is proposed, comprising an electric motor and a converter for supplying power to the electric motor, wherein the electric motor comprises a motor housing from which connecting cables lead out and the converter comprises a housing base on which a power connection is arranged, wherein coupling points are provided on the power connection to which the connecting cables can be connected in a current-conducting manner.

[0012] According to the invention, it is proposed that a carrier is arranged between the electric motor and the converter, wherein the carrier comprises a carrier part and a carrier part cover which enclose a connection space in which the coupling points are arranged.

[0013] A coupling point can be a screw or plug connection designed for a required current flow. In particular, the design is for use in a motor vehicle in which the motor unit according to the invention can be part of the drive train.

[0014] Preferably, the power connection comprises a flange part which is arranged between the lower part and the support part such that a gap is formed between the flange part, the support part and the lower part.

[0015] Furthermore, it can be provided that the intermediate space is sealed off from the terminal compartment and the interior of the converter by means of seals. In a preferred embodiment, the power connection can also be fixed to the lower part. The interior space encloses the components of the converter. The power connection thus closes off the interior of the converter in such a way that sealing against the environment is ensured even before mounting on the flange part.

[0016] Furthermore, it can be provided that the lower part has a connection side with a connection level and a sealing level arranged parallel thereto, wherein fixing points for fastening the converter to the support part are provided in the connection level.

[0017] In a preferred embodiment, the fixing points are arranged relative to one another in such a way that a mechanical connection is made between the converter and the carrier part and a continuous electrical contact is made, so that the EMC interference emission is ensured at a sufficiently low level.

[0018] Furthermore, the flange part of the power connection can comprise at least three receptacles in which the busbars with the coupling points arranged thereon can be fixed permanently or detachably.

[0019] In a further preferred embodiment, each busbar can have a connection surface in which the coupling point is arranged, wherein an insulating collar radially encloses the connection surface in sections.

[0020] The invention is explained below with reference to the figures. The figures show in detail:

[0021] Fig. 1 : Motor unit

[0022] Fig. 2: Connection side of the converter

[0023] Fig. 3: Power connection installed

[0024] Fig. 4: Connection compartment

[0025] Figure 1 shows the motor unit with the electric motor 8 and the converter 1 for supplying power to the electric motor. The electric motor 8 and the converter 1 are each housed in a separate housing. The converter itself is designed to be enclosed. The motor is sealed off from the environment and the interior of the converter by flanging the converter onto it. The motor unit is formed by coupling the electric motor 8 and the converter 1 together by means of the carrier 6, consisting of the carrier part 13 and the carrier part cover 24. The converter 1 is thus connected to the motor vehicle via the motor housing 5.

[0026] Also visible are the fixing points 12, in this case a screw connection 12, provided between the lower part 3 and the support part 13. The fixing points 12 are provided in the connection level 10 for fastening the converter 1 to the support part 13. The number of fixing points 12 can also be clearly seen in Fig. 2 and their arrangement relative to one another is crucial for the mechanical connection between the converter 1 and the support part 13 and for the all-round electrical contacting, which ensures that EMC interference is kept at a sufficiently low level.

[0027] Figure 2 shows a section of the connection side 9 of the converter 1 with the DC connection 22 for supplying power to an electric motor 8 and the connections 23 for controlling the converter 1.

[0028] This illustration essentially shows the support part 13, via which the converter 1 is attached to the motor housing 5. The support part 13 is shown in this view without the support part cover 24, so that the connection space 26 of the support part 13 can be seen, in which the three connection cables 25a, b, c run or are arranged between the power connection 7 and the electric motor 8.

[0029] The lower part 3 of the converter 1 is designed like a trough, and all components for conducting current between the DC connection 22 and the power connection 7 (not shown here), including the control board and the IGBT modules, are located inside. The lower part 3 of the converter 1 is also closed with a cover (not shown).

[0030] Fig. 3 shows the power connector 7, which consists of a flange part 14 and at least three busbars 15a, b, c. The power connector 7 is attached to the lower part 3. The attachment is made to a sealing plane 11a on the lower part 3, with a seal 21a provided between the flange part 14 and the sealing surface of the sealing plane 11a. The attachment can be made, for example, by means of a screw connection.

[0031] Parallel to the sealing plane 11a, the lower part 3 has a connection plane 10, wherein the connection plane 10 provides means 12, here threaded holes, so that the converter 1 can be fastened to the support part 13 by means of a screw connection. Due to the parallel offset of the sealing plane 11a and the connection plane 10, the flange of the flange part 14 can be arranged between the lower part 3 and the support part 13, wherein seals 21a, b are provided between the contact surfaces or sealing planes 11a, b. In the illustrated embodiment, an intermediate space 27 is provided which is formed between the flange part 14, the support part 13 and the lower part 3.

[0032] This intermediate space 27 hermetically separates the interior of the converter 1 from the connection space 26 in the carrier 6.

[0033] The busbars 15 a, b, c are guided through receptacles 18 a, b, c in the flange portion 14 of the power connector 7. The receptacles 18 a, b, c are designed such that the busbars 15 a, b, c are firmly positioned in them. This can be achieved by casting or a form-fitting and sealed connection. To ensure the correct pressing of the installed seals 21 a, b, respectively, the grooves in the flange portion are designed accordingly.

[0034] In the lower part 3 as well as in the support part 13, bushings 16a, b are provided through which the busbars 15a, b, c extend.

[0035] This design also allows for the use of an alternative power connection, so that the converter can also be electrically connected to an electric motor as a loose converter via a cable connection.

[0036] Figure 4 shows the terminal compartment, clearly showing the power connection between converter 1 and electric motor 8. The busbar 15a shown runs through the flange 14, and a screw connection can be seen, via which the electrical components in the converter are connected to the busbar 15. A connecting cable 25a is also shown, which leads out of the motor housing 5. At coupling point 28a, the connecting cable 25a is connected to the busbar 15 of the power connection 7. Here, this connection is done using a screw connection.

[0037] The proposed flange part 14 further comprises an insulating collar 20, which advantageously restricts accessibility to the connection point. The insulating collar 20 partially encloses the connection surface in the radial direction. Also shown is the support part 13, which encloses a connection space (26) that can be closed with a support part cover 24. The flange part 14 extends through the feedthrough 16b into the connection space 26, so that the connecting cables 25 of the electric motor 8 can be easily connected to the busbars 15a, b, c when the converter 1 is mounted on the support part 13. After the wiring is complete, the support part cover 24 can be screwed on.

[0038] List of reference symbols

[0039] 1 inverter

[0040] 2 housings

[0041] 3 Lower housing part

[0042] 4 Cooling channel system

[0043] 5 Motor housing

[0044] 6 carriers

[0045] 7 Power connection

[0046] 8 electric motor

[0047] 9 Connection side

[0048] 10 connection level

[0049] 11 a, b Sealing level

[0050] 12 screw connection

[0051] 13 Support part

[0052] 14 Flange part

[0053] 15a, b, c Busbars

[0054] 16a, b Feedthrough 17 Upper part 18a, b, c Receptacle

[0055] 19 Connection surface

[0056] 20 insulating collars

[0057] 21 a, b seal

[0058] 22 DC connection

[0059] 23 Control connection

[0060] 24 carrier part covers

[0061] 25a, b, c connecting cable

[0062] 26 Connection compartment

[0063] 27 space

[0064] 28a, b, c coupling point

[0065] 29 Interior

Claims

Patent claims 1. Motor unit, comprising an electric motor (8) and a converter (1) for supplying power to the electric motor (8), wherein the electric motor (8) comprises a motor housing (5) from which connecting cables (25a, b, c) lead out and the converter (1) comprises a housing lower part (3) on which a power connection (7) is arranged, wherein coupling points (28a, b, c) are provided on the power connection (7), to which the connecting cables (25a, b, c) can be connected in a current-conducting manner, characterized in that a carrier (6) is arranged between the electric motor (8) and the converter (1), wherein the carrier (6) comprises a carrier part (13) and a carrier part cover (24) which enclose a connection space (26) in which the coupling points (28a, b, c) are arranged.

2. Motor unit according to claim 1, characterized in that the power connection (7) comprises a flange part (14) that is arranged between the lower part (3) and the support part (13) in such a way that an intermediate space (27) is formed between the flange part (14), the support part (13) and the lower part (3).

3. Motor unit according to claim 2, characterized in that the intermediate space (27) is sealed off from the connection space (26) and an interior space (29) of the converter (1) by means of seals (21a, b).

4. Motor unit according to claim 2, characterized in that the power connection (7) is fixed to the lower part (3).

5. Motor unit according to claim 1, characterized in that the lower part (3) has a connection side (9) with a connection plane (10) and a sealing plane (11a) arranged parallel thereto, wherein fixing points (12) for fastening the converter (1) to the support part (13) are provided in the connection plane (10).

6. Motor unit according to claim 5, characterized in that the fixing points (12) are arranged relative to one another in such a way that a mechanical connection is made between the converter (1) and the support part (13) and a circumferential electrical contact is made, so that the EMC interference emission is ensured at a sufficiently low level.

7. Motor unit according to claim 2, characterized in that the flange part (14) of the power connection (7) comprises at least three receptacles (18a, b, c) in which the busbars (15a, b, c) with the coupling points (28) arranged thereon can be fixed permanently or detachably.

8. Motor unit according to claim 1, characterized in that each busbar (15a, b, c) has a connection surface (19a, b, c) in which the coupling point (28) is arranged, wherein an insulating collar (20) radially encloses the connection surface (19a, b, c) in sections.

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