Drive device comprising an electric motor and an inverter and motor vehicle

Abstract

A drive device, in particular for a motor vehicle (1), comprising an electric motor (2) and an inverter (4), wherein the electric motor (2) comprises at least one electrically conductive motor contact element (7) for electrically contacting a respective electrically conductive inverter contact element (6) of the inverter (4), wherein the motor contact element (7) is mounted directly or via a motor sealing means (16) on a motor housing component (13) of a motor housing (14) of the electric motor (2) and the inverter contact element (6) is mounted directly or via an inverter sealing means (11) on an inverter housing component (8) of an inverter housing (9) of the inverter (4), wherein the motor contact element (7) and the inverter contact element (6) are mechanically fastened to one another by a fastening means (21),wherein the fastening means (21) and a respective housing-external section of the motor contact element (7) and the inverter contact element (6) are accommodated in a liquid-tight receiving space (26) which is formed at least in sections by the inverter housing component (8) and the motor housing component (13). characterized in that the motor contact element (7) or the inverter contact element (6) has an opening (17) through which the fastening means (21) extends, wherein a receiving space sealing means (19) is arranged between the motor housing component (13) and the inverter housing component (8) in order to liquid-tightly close off the liquid-tight receiving space (26) on a side of the opening (17) of the motor contact element (7) facing the inverter contact element (6) or on a side of the opening (17) of the inverter contact element (6) facing the motor contact element (7).

Description

The invention relates to a drive device, in particular for a motor vehicle, comprising an electric motor and an inverter, wherein the electric motor comprises at least one electrically conductive motor contact element for electrically contacting a respective electrically conductive inverter contact element of the inverter, wherein the motor contact element is held directly or via a motor sealing means on a motor housing component of a motor housing of the electric motor and the inverter contact element is held directly or via an inverter sealing means on an inverter housing component of an inverter housing of the inverter, wherein the motor contact element and the inverter contact element are mechanically fastened to one another by a fastening means, wherein the fastening means and a respective housing-external section of the motor contact element and of the inverter contact element are accommodated in a liquid-tight accommodation space which is formed at least in sections by the inverter housing component and the motor housing component. In addition, the invention relates to a motor vehicle.Inverters are frequently used to energize electric machines, in particular powerful electric machines, which can be used as a drive motor in a motor vehicle, for example, in order to provide an AC voltage for operating the electric motor. Such an inverter can be supplied in motor vehicles, for example, by a direct current network of the motor vehicle or by a vehicle battery.It is often advantageous here to initially configure the inverter and the electric machine as separate components. However, since high powers can be carried via electrical connections between the inverter and the electric machine, reliable contact protection and protection against environmental influences, for example against penetrating liquids, should be achieved for such a connection.A common approach for this is to use a sealed space, also called a terminal box, via which the separately non-sealed electric machine is connected to the separately non-sealed inverter. However, pressure compensation or medium exchange between inverter and electric machine can take place via the clamping connection box, as a result of which, for example, cooling medium, oil or other contamination is exchanged via this clamping connection box. In addition, as a result, a relatively large component including the electric machine and the inverter needs to be sealed. This can require complex constructions or greatly restrict permissible tolerances.The publication DE 10 2014 213 973 A1 proposes a connection arrangement for the mechanically flexible electrical connection of two high-voltage components in a vehicle, for example an electric motor and a control unit. The components are connected by a high voltage cable arrangement and a low voltage cable arrangement, which are jointly surrounded by an elastically bendable sheath. The casing can be hermetically coupled to at least one of the housings of the high-voltage components in order to be able to prevent fluids from entering the interior of the casing. The housings of the high voltage components are preferably hermetically sealed. It is problematic here that the application of the common sheathing and the hermetically sealed attachment to the housings is relatively complicated and at most completely automatable with great effort.The generic publication WO 2012 / 59 831 A1 discloses a connecting module for electrically coupling an electric motor or hybrid motor to a converter.The connection module is flat and has busbars, one ends of which form motor-side contacts and the other ends of which form the converter-side contacts, wherein the busbars are embedded in a matrix of an electrically non-conductive material.JP 2015-62 344 A discloses a connecting module for connecting a motor to an inverter. The connection module comprises an upper and a lower half which are movable relative to each other by connection via an elastic element 60 which also has a sealing function, in order to damp vibration transmission between the motor and the inverter.The document DE 10 2007 052 017 A1 relates to a power converter connector for connecting a power converter to an electric motor.The object of the invention is thus to seal an electrical contact region between electric motor and inverter against the penetration of liquids with little technical complexity.The object is achieved by a drive device of the type mentioned at the beginning, wherein the motor contact element or the inverter contact element has an aperture through which the fastening means passes, wherein a receptacle space sealing means is arranged between the motor housing component and the inverter housing component in order to seal the liquid-tight receptacle space liquid-tightly on a side of the aperture of the motor contact element facing the inverter contact element or on a side of the aperture of the inverter contact element facing the motor contact element.It is thus proposed to carry out the sealing of the receiving space with respect to liquids at least partially by components of the housing of the electric motor and of the inverter. Since the motor contact element and the inverter contact element are fastened to one another without an additional cable connection, a very compact construction can be achieved overall and the receiving space can thus be sealed off with simple means in a few working steps.The inverter can be, in particular, a pulse inverter. For example, a pulse-controlled three-phase bridge inverter may be used. If a polyphase voltage is provided for the electric motor by the inverter, a plurality of pairs of motor contact elements and inverter contact elements can be used for this purpose, with one phase being passed over each of these pairs. It is possible here for a separate receiving space to be formed for each pair of motor contact element and inverter contact element. Alternatively, however, a common receiving space can also be formed, in which all pairs of motor contact element and inverter contact element are received.The receiving space is to be liquid-tight in particular with respect to cooling liquids, lubricating liquids and / or liquids occurring in the environment of the receiving space, i.e. in particular with respect to water and oil. Depending on the specific operating situation, it may be sufficient if the receiving space is, for example, water-tight. Preferably, however, the receiving space is tight with respect to liquids at least for several minutes, for example 5, 10, 20 or 60 minutes or preferably for several hours.The motor contact element can be surrounded by the motor housing component or the motor housing component and the motor sealing means in such a way that the motor housing is sealed off in a liquid-tight manner at least in the region of the motor contact element, and / or the inverter contact element can be surrounded by the inverter housing component or the inverter housing component and the inverter sealing means in such a way that the inverter housing is sealed off in a liquid-tight manner at least in the region of the inverter contact element. In this way, in particular, a fluid exchange between the receiving space and the interior of the inverter housing or motor housing can be avoided.Preferably, the inverter housing and / or the motor housing are sealed liquid-tight. This also means, in particular, that further connections or shaft feedthroughs of these components are likewise designed to be liquid-tight. With respect to the inverter, for example, a connection for a DC voltage or for control signals can also be sealed. In the electric motor, in particular, a passage of the shaft is sealed in a liquid-tight manner. In addition, connections for sensors, a controller or the like can likewise be sealed, for example. A liquid-tight seal of the entire inverter housing or motor housing makes it possible, for example, to flood these housings with cooling fluid or the like.The motor contact element or the inverter contact element has an aperture through which the fastening means extends. As a result, robust contacting of these elements can be achieved with technically simple means.The fastening means may be a screw which engages a thread formed by the inverter contact element or the motor contact element. In particular, that one of the contact elements which does not have the thread can have the aperture through which the screw is guided. For example, a screw head can rest directly or via a washer or the like on the edge of the aperture and thus press the contact element having the aperture against the contact element having the thread.Between the motor housing component and the inverter housing component, a receptacle space sealing means is arranged in order to seal the liquid-tight receptacle space liquid-tightly on a side of the aperture of the motor contact element facing the inverter contact element or on a side of the aperture of the inverter contact element facing the motor contact element. The receptacle space sealing means can be pre-assembled on the motor housing component or the inverter housing component before assembly or can be inserted between these components during assembly. Preferably, the seal to the environment on this opening side can be effected jointly by the receptacle space sealing means and the motor and inverter housing component. The termination to the electric motor can be effected by the motor housing component, the motor contact element and optionally the motor sealing means. Towards the inverter, the termination can be effected by the inverter housing component, the inverter contact element and optionally the inverter sealing means. The receiving space can thus be sealed as it were automatically at least on one side of the aperture within the scope of the mechanical fastening of the motor contact element and of the inverter contact element to one another. This enables a simple construction of the drive device according to the invention, wherein the assembly can be automated in a particularly simple manner.The drive device can have a closure element which is connected directly or via a closure sealing means to the motor housing component or the inverter housing component in order to close off the liquid-tight receiving space in a liquid-tight manner on a side of the aperture of the motor contact element facing away from the inverter contact element or on a side of the aperture of the inverter contact element facing away from the motor contact element. The receiving space can thus be sealed in a liquid-tight manner in particular by the closure element being connected to the motor housing component or the inverter housing component after the motor contact element and the inverter contact element have been mechanically fastened to one another. This can be done, for example, by screwing, adhesive bonding, clipping or the like. Overall, the liquid-tight receiving space can thus be constructed in a few working steps that can be easily automated. The closure element can be in particular a plate-shaped closure element which rests directly or via the closure sealing means on a circumferential projection of the motor housing component or of the inverter housing component.The motor housing component or the inverter housing component can form at least one spacer, on which the closure element rests directly or via the closure sealing means and which spaces the closure element from the aperture. In this way, a receiving space for a part of the fastening means protruding beyond the opening, for example a screw head or the like, can be provided with simple means.The motor housing component may be connected to another motor housing component via a motor housing seal and / or the inverter housing component may be connected to another inverter housing component via an inverter housing seal. This makes it possible, for example, to use different materials, shapes or the like for different housing components. For example, a large part of the housing can be formed from metal, while the component enclosing the motor contact element or the inverter contact element is formed from plastic, for example, in order to ensure insulation of the corresponding contact element.The receiving space can be surrounded at least partially, that is to say for example in a specific angular range, by a shielding element, for example a sheet metal or a conductive grid, in order to reduce or suppress radiation or irradiation of electromagnetic radiation in the contact region between the motor contact element and the inverter contact element.In addition to the drive device according to the invention, the invention relates to a motor vehicle which comprises a drive device according to the invention.Further advantages and details of the invention are evident from the following exemplary embodiments and the associated drawings. The following are shown schematically: FIG. 1 shows an exemplary embodiment of a motor vehicle according to the invention, which comprises an exemplary embodiment of a drive device according to the invention, and FIGS. 2 to 5 show detailed views of an exemplary embodiment of the drive device according to the invention or of the components thereof.FIG. 1 shows a motor vehicle 1 which comprises an electric motor 2 which is intended to be supplied by a battery 3 or an on-board power supply system. The electric motor 2 can be, in particular, a drive motor of the motor vehicle 1. The drive train of the motor vehicle and the shaft of the electric motor 2 connected to it are not shown for reasons of clarity.The electric motor 2 is to be supplied with a three-phase alternating voltage, while the battery 3 or a vehicle grid provides a direct voltage. Therefore, the electric motor 2 is connected to the battery 3 or the on-board power supply system via an inverter 4. The electric motor 2 and the inverter 4 together form a drive device 29 for the motor vehicle 1. the inverter 4 has a DC voltage connection 5 for connection to the battery 3 and a plurality of inverter contact elements 6, which are conductively connected to motor contact elements 7 in order to enable the electric motor 2 to be energized. The inverter 4 is preferably a pulse inverter which is controlled by a control device, not shown, of the motor vehicle 1.The inverter contact elements 6 are intended to be connected to the motor contact elements 7 in a liquid-tight receiving space in order to prevent, for example, water from splashing from the surroundings of the motor vehicle 1 or cooling liquid of the electric motor 2 or the like from entering the contact region. Here, in the motor vehicle 1, a separate accommodation space is used for each pair of inverter contact element 6 and motor contact element 7, for example. The procedure for providing such a receiving space, which is illustrated in detail below, can, however, also be used if a common receiving space is to be provided for a plurality of these pairs.Using the example of one of the contacts between inverter contact element 6 and motor contact element 7, it is explained below with reference to FIGS. 2 to 5 how such contacting and the provision of a liquid-tight receiving space 26 can be realized with simple technical means and in a manner that can be easily automated. FIG. 2 shows a detailed view of the inverter 4 in the region of one of the inverter contact elements 6, the inverter contact element 6 being held on an inverter housing component 8 of an inverter housing 9 of the inverter 4 via an inverter sealing means 11. The inverter housing component 8 can consist, for example, of plastic or another insulating material in order to ensure adequate insulation even when high voltages or powers are provided via the inverter contact element 6. In principle, the entire housing 9 could be formed from a single housing component 8. However, it is often advantageous to form the housing 9 from a plurality of housing components 8, 24, wherein an inverter housing seal 10 is preferably used in order to ensure that the inverter housing 9 is liquid-tight at least in the region of the inverter contact element 6, but preferably over the entire housing.The inverter contact element 6 can form a thread 25 in order to enable a robust mechanical fastening or a robust electrical contacting of the inverter contact element 6 with the motor contact element 7 in a simple manner, as will be explained in more detail later.FIG. 3 shows a detailed view of the electric motor 2 in the region of the motor contact element 7. the motor contact element 7 is held on a motor housing component 13 of the motor housing 14 of the electric motor 2, wherein the motor sealing means 16 is used for more robust sealing of the housing in the region of the motor contact element 7. In order to achieve overall a robust sealing of the motor housing 14, the motor housing component 13 is connected to at least one further motor housing component 12 of the motor housing 14 via motor seals 15.The motor contact element 7 has an aperture 17 via which, as will be explained in more detail below, the contacting with the inverter contact element 6 takes place. In order to be able to provide a liquid-tight receiving space for the contact region in a few and simple production steps, spacers 18, receiving space sealing means 19 and closure sealing means 20 are provided on the motor housing component 13. The effect of these components will be explained in more detail below with reference to FIGS. 4 and 5. The receptacle space sealing means 19 or closure space sealing means 20 can be injection-molded, for example, onto the motor housing component 13. Alternatively, it would also be possible, for example, to design these elements as separate components which are arranged at the position shown in FIG. 3 only within the scope of the assembly of different components explained below.The various sealing means or seals can be formed, for example, from rubber or another elastomer, a fluid-tight adhesive layer or the like.FIG. 4 shows the connection of the inverter contact element 6 to the motor contact element 7. For this purpose, the inverter housing 9 is arranged with respect to the motor housing 14 in such a way that, for each pair of the contact elements to be connected, the aperture 17 of the respective motor contact element 7 is aligned with the thread 25 of the respective inverter contact element 6. Thus, a connection can be effected simply by the fastening means 21 being guided through the aperture 17 and fastened to the inverter contact element 6.In the example, a screw is used as the fastening means 21, whereby the fastening can be effected by simply screwing the screw into the thread 25 through the aperture 17. In this case, the receptacle space sealing means 19 seal off the remaining gap between the motor housing component 13 and the inverter housing component 8 in a liquid-tight manner, with the result that that part of the receptacle space 26 which receives the contact and lies on the left of the aperture 17 in FIG. 4 is automatically sealed off in a liquid-tight manner. The seal from the environment is effected jointly by the motor housing component 13, the inverter housing component 8 and the receptacle space sealing means 19; in addition, the receptacle space 26 is sealed off from the interior space 27 of the inverter housing 9 by the inverter contact element 6, the inverter sealing means 11 and the inverter housing component 8. A seal with respect to the interior 28 of the motor housing 14 takes place jointly by the motor contact element 7, the motor housing component 13 and the motor sealing means 16.In order to close off the part of the receiving space 26 situated to the right of the aperture 17 in FIG. 4 in a liquid-tight manner, an in particular plate-shaped closure element 22 is, as is illustrated in FIG. 5, placed on the spacers 18 or the closure sealing means 20 arranged thereon and, for example, glued or screwed or clamped there. Thus, the receiving space 26 is now closed on all sides in a liquid-tight manner.For the purpose of electrical shielding, the region of the receiving space can be surrounded at least partially by an additional shielding element 23, for example a conductive grid or a conductive plate. If, for example, the motor housing component 12 and the inverter housing component 24 are also conductive, electromagnetic shielding of the drive device can also be realized with little effort.In an alternative, not shown, the through-opening 17 could also be a through-opening of the inverter contact element 6 and the thread 25 could be formed by the motor contact element 7. The further described components can be adapted accordingly.

Claims

Drive device, in particular for a motor vehicle (1), comprising an electric motor (2) and an inverter (4), wherein the electric motor (2) comprises at least one electrically conductive motor contact element (7) for electrically contacting a respective electrically conductive inverter contact element (6) of the inverter (4), wherein the motor contact element (7) is held directly or via a motor sealing means (16) on a motor housing component (13) of a motor housing (14) of the electric motor (2) and the inverter contact element (6) is held directly or via an inverter sealing means (11) on an inverter housing component (8) of an inverter housing (9) of the inverter (4), wherein the motor contact element (7) and the inverter contact element (6) are mechanically fastened to one another by a fastening means (21), wherein the fastening means (21) and a respective section of the motor contact element (7) and of the inverter contact element (6) external to the housing are accommodated in a liquid-tight accommodation space (26) which is formed at least in sections by the inverter housing component (8) and the motor housing component (13), characterized in that the motor contact element (7) or the inverter contact element (6) has an aperture (17) through which the fastening means (21) extends, wherein an accommodation space sealing means (19) is arranged between the motor housing component (13) and the inverter housing component (8) in order to seal the liquid-tight accommodation space (26) liquid-tightly on a side of the aperture (17) of the motor contact element (7) facing the inverter contact element (6) or on a side of the aperture (17) of the inverter contact element (6) facing the motor contact element (7).Drive device according to Claim 1, characterized in that the motor contact element (7) is surrounded by the motor housing component (13) or the motor housing component (13) and the motor sealing means (16) in such a way that the motor housing (14) is closed off in a liquid-tight manner at least in the region of the motor contact element (7), and / or in that the inverter contact element (6) is surrounded by the inverter housing component (8) or the inverter housing component (8) and the inverter sealing means (11) in such a way that the inverter housing (9) is closed off in a liquid-tight manner at least in the region of the inverter contact element (6).Drive device according to Claim 1 or 2, characterized in that the inverter housing (9) and / or the motor housing (14) are closed off in a liquid-tight manner.Drive device according to one of the preceding claims, characterized in that the fastening means (21) is a screw which engages in a thread (25) formed by the inverter contact element (6) or the motor contact element (7).Drive device according to one of the preceding claims, characterized in that it has a closure element (22) which is connected directly or via a closure sealing means (20) to the motor housing component (13) or the inverter housing component (8) in order to close off the liquid-tight receiving space (26) in a liquid-tight manner on a side of the aperture (17) of the motor contact element (7) facing away from the inverter contact element (6) or on a side of the aperture (17) of the inverter contact element (6) facing away from the motor contact element (7).Drive device according to Claim 5, characterized in that the motor housing component (13) or the inverter housing component (8) forms at least one spacer (18), on which the closure element (22) rests directly or via the closure sealing means (20) and which spaces the closure element (22) from the aperture (17).Drive device according to one of the preceding claims, characterized in that the motor housing component (13) is connected to a further motor housing component (12) via a motor housing seal (15), and / or in that the inverter housing component (8) is connected to a further inverter housing component (24) via an inverter housing seal (10).Motor vehicle, characterised in that it comprises a drive device (29) according to one of the preceding claims.

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