ELECTRICAL DRIVE DEVICE AND DRIVE ARRANGEMENT

Description

[0001] The invention relates to an electric drive device and a drive arrangement with an electric drive device and an internal combustion engine.

[0002] Various electric drive systems are known that are used in drive trains or drive arrangements, particularly for hybrid vehicles. A hybrid drive system, for example, is known from DE 11 2015 006 071 T5.

[0003] Such electric drive devices comprise at least one electric rotary machine arranged in a housing and power electronics. The power electronics serve to control or supply the electric rotary machine(s) with electrical energy, with an electric rotary machine typically being designed as a multi-phase three-phase machine.

[0004] In addition, the power electronics may include a control interface for connecting a motor vehicle control unit and / or an electrical interface for connecting an energy storage device, such as a battery. The power electronics may also include the control unit itself. The control unit serves to control the electric rotating machine(s). Several control or electrical interfaces may be provided, depending on the number of devices to be connected.

[0005] Typically, the power electronics unit and its housing are fixedly mounted on a housing of a machine unit of the electric drive device comprising the electric rotary machine(s). For the purpose of controlling or supplying power to the electric rotary machine(s), at least one electrically conductive connection, but preferably several electrically conductive connections, is established between the power electronics unit and the machine unit. Connections between power electronics and machine units are known, for example, for motor vehicle actuators from WO 2018 / 197473 A1 and for heating circulation pumps from EP 2 072 828 A1.

[0006] When current flows through at least one of these electrical connections, a high-frequency electromagnetic field can be created, which is transmitted via the corresponding housing and through these to the environment.

[0007] This high-frequency electromagnetic field may impair the function of a radio in the MW or VHF range and / or cause interference with electronic control units in or in the immediate vicinity of the motor vehicle equipped with the electric drive device.

[0008] In order to improve the electromagnetic compatibility of known electrical drive devices, earthing of the housings of the power electronics and the housings of the electric rotating machine(s) is currently being implemented.

[0009] Typically, separate elements such as grounding cables with corrosion protection are used for this purpose. However, both their manufacture and the integration of such grounding systems into an electric drive system involve considerable effort.

[0010] Based on this, the present invention is based on the object of providing an electric drive device and a drive arrangement equipped therewith, which increase the electromagnetic compatibility in a cost-effective manner.

[0011] The object is achieved by the electric drive device according to claim 1. Advantageous embodiments of the electric drive device are specified in subclaims 2 to 7. In addition, a drive arrangement comprising the electric drive device is provided according to claim 8.

[0012] The features of the claims can be combined in any technically reasonable manner, whereby the explanations from the following description as well as features from the figures can also be used to comprise additional embodiments of the invention.

[0013] The invention relates to an electric drive device, comprising a machine unit with a machine housing and at least one electric rotary machine arranged therein, and comprising power electronics with an electronics housing and control electronics arranged therein. At least one of the two housings has at least one projection for the purpose of defined positioning of the machine unit and the power electronics to one another during and / or after assembly. The respective other housing has a recess that is complementary in shape and size to accommodate the projection. It is provided that the projection and the material forming the recess are electrically conductive at least in sections and that the projection and the recess are electrically conductively connected to an earth for the purpose of earthing the power electronics or the machine unit.

[0014] Accordingly, the invention provides that projections and recesses present on the housings to be mounted or already mounted fulfill a dual function, namely, on the one hand, to facilitate assembly processes with regard to carrying out defined relative movements of the housings to one another during assembly and fixing in the final target position, whereby the two housings are guided in their relative movements relative to one another by means of the projection and recess, and, on the other hand, to ground the power electronics and / or the machine unit. In the assembled state, the projection and recess fix the two housings in at least two translational degrees of freedom and two rotational degrees of freedom. With a preferred arrangement of several projections and complementary recesses, all three rotational degrees of freedom can be taken away from the two housings.

[0015] In the sense of the invention, the machine unit can also be understood as a combination of a drive unit, such as the electric rotary machine, with transmission elements or a transmission.

[0016] In this case, the power electronics is essentially a control device for controlling the machine unit.

[0017] Control electronics in the sense of the invention is understood to mean at least one electronic component, but usually a system of several electronic components that are electrically coupled to one another.

[0018] In this case, earthing refers to the contact of an electrical pole, in particular the negative pulse or the so-called ground, with the body or a supporting frame of the motor vehicle.

[0019] If the machine unit has an earthing system, the power electronics can be earthed via the electrically conductive connection implemented according to the invention via the machine unit.

[0020] If the power electronics have an earthing system, the machine unit can be earthed via the electrically conductive connection implemented according to the invention via the power electronics.

[0021] In a preferred embodiment, it is provided that the machine unit has an earthing and the power electronics are also earthed via the electrically conductive connection and the machine unit.

[0022] According to a further aspect of the invention, the projection is formed on the electronics housing and the recess is formed in the machine housing.

[0023] The projection is made of a corrosion-resistant material, such as stainless steel.

[0024] According to the invention, the projection has the shape of a pin and the recess has the shape of a bore in which the pin is received.

[0025] This means that the projection essentially has a slender cylindrical shape, with the recess being designed accordingly as a slender hollow cylinder.

[0026] Accordingly, the pin can be a separate element, with a fixed and electrically conductive connection being established between the respective housing on which the pin is arranged and the pin. However, according to the invention, this does not preclude the pin from also being an integral part of a housing.

[0027] In a supplementary embodiment, the pin sits in the bore with a press fit.

[0028] The press fit creates a force-locking fixation between the pin and the bore.

[0029] Furthermore, according to the invention, an electrically conductive tolerance sleeve is arranged between the pin and the bore.

[0030] A tolerance sleeve, also known as a tolerance ring, is used to bridge gaps between rotationally symmetrical and interlocking machine elements. The tolerance sleeve rests resiliently on both the pin and the inner wall of the recess. The tolerance sleeve can be essentially wave-shaped along its circumferential direction.

[0031] In this case, the tolerance sleeve serves to position the pin in the recess and, accordingly, to mechanically fix it in the aforementioned degrees of freedom. In addition, the tolerance sleeve also serves to create the electrically conductive connection for grounding purposes.

[0032] In particular, it can be provided that the tolerance sleeve is made of stainless steel, at least in part.

[0033] According to a further aspect of the electric drive device, a seal is arranged between the two housings.

[0034] Preferably, this seal surrounds the pin radially and is designed as a fluid seal to prevent the entry of lubricants from the machine housing into the power electronics, and / or to prevent the entry of moisture from the environment into the machine housing or the electronics housing.

[0035] The seal is preferably designed as an O-ring. However, this does not preclude the possibility of the seal having a different design.

[0036] In a further embodiment, plug-in connection elements are arranged on both housings, which are designed to be plugged into one another along a plug-in connection direction to produce at least one electrically conductive plug-in connection for the purpose of realizing a respective electrical connection between the machine unit and the power electronics, wherein the plug-in connection direction runs parallel to the longitudinal extension direction of the pin.

[0037] Accordingly, it is provided that the two housings are brought closer together during assembly in their relative movements such that, during the assembly movement, pin-shaped projections are inserted into hollow cylindrical recesses, thus precisely defining the direction of the assembly movement. This direction of movement also corresponds to the plug-in connection direction in which the plug-in connection elements are to be inserted into one another, so that the inventive design of the housings not only facilitates the assembly and positioning of the housings relative to one another, but also facilitates electrical contacting and enables the automated execution of the assembly.

[0038] According to a further advantageous embodiment of the invention, the material of the machine housing and / or the electronics housing is an aluminum alloy or a magnesium alloy.

[0039] Furthermore, according to the invention, a drive arrangement is provided which has an electric drive device according to the invention and an internal combustion engine, wherein the internal combustion engine is or can be coupled in a rotationally fixed manner to a rotor of the electric rotary machine.

[0040] The invention described above will be explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, and it should be noted that the embodiments shown in the drawings are not limited to the dimensions shown. It is shown in Fig. 1: an electric drive device according to the invention in a perspective view, Fig. 2: a section of the electric drive device during an assembly step and Fig. 3: a sectional view of the electric drive device.

[0041] In Fig. 1 an electric drive device 1 according to the invention is shown in perspective.

[0042] The electric drive device 1 comprises a machine unit 10 and power electronics 20.

[0043] The machine unit 10 has a machine housing 11 in which at least one electric rotary machine is arranged. This serves to integrate the electric drive device 1 into a drive arrangement of a hybrid motor vehicle, which further comprises an internal combustion engine for implementing various driving modes of the hybrid motor vehicle. The coupling to the internal combustion engine is realized at the connection side 18 of the machine housing 10. The connection side 18 of the machine housing 10 is designed as a hub 17 with splines. Accordingly, torque can be transmitted between the electric drive device and the internal combustion engine.

[0044] The power electronics 20 with its electronics housing 21 is arranged on an upper side 18 of the machine housing 11 of the machine unit 10. The power electronics 20 comprises control electronics (not shown here) in the electronics housing 21 and essentially serves to control the machine unit 10, with several electrically conductive connections being implemented between the power electronics 20 and the machine unit 10 for this purpose. The electronics housing 21 is arranged with a connection side 28, which corresponds to an underside of the power electronics 20, on the upper side 18 of the machine housing 11 and is firmly connected to the machine housing 11. This firm connection is implemented via screw or bolt connections at a respective corner area of the power electronics 20.For this purpose, the electronics housing 21 forms connecting flanges 27 on its connection side 28, through which corresponding screws or bolts are passed and inserted into the machine housing 11 in order to realize the firm connection of the two housings 11, 21 with each other.

[0045] Fig. 2 shows a section of the electric drive device 1 during an assembly step.

[0046] During the assembly step, the power electronics 20 is arranged with its connection side 28 on the top side 18 of the machine unit 10. The snapshot of the assembly step shows the power electronics 20 in a position spaced from the top side 18 of the machine unit 10, whereby a projection 22 and plug connection elements 41 arranged on protruding shaped elements 42 of the electronics housing 21 can be seen on the connection side 28 of the electronics housing 21. A recess 12 and shaped elements 43 of the machine housing 11 can be seen on the top side 18 of the machine housing 11. The shaped elements 43 of the machine housing 11 are designed as hollow cylindrical and slot-shaped recesses in the top side 18 of the machine housing 11, in which plug connection elements of the machine housing 11 (not visible here) are arranged.

[0047] The shaped elements 43 of the electronics housing 21 are designed to complement each other in terms of their shape, size, and position to a shaped element 43 of the machine housing 21. The plug-in connection elements 41 of the electronics housing 21 are designed as pin-shaped elements protruding from the connection side 28 of the electronics housing 21.

[0048] The recess 12 has the shape of a bore 13. The projection 22 has a slender cylindrical shape, so that the projection is designed as a pin 23. The projection 22 is also complementary to the recess 12 in terms of its size and position.

[0049] The longitudinal extension directions of the bore 13, the pin 23 and the plug-in connection elements 41 run parallel to each other, so that a movement direction 2 of an assembly movement also takes place parallel thereto.

[0050] When the power electronics 20 moves along the direction of movement 2 of the assembly movement towards the machine unit 10, the plug connection elements 41 of the electronics housing 21 are inserted into the plug connection elements of the machine housing 11 and the pin 23 is inserted into the bore 13.

[0051] A plug connection direction 40, along which the plug connection elements 41 are configured to be plugged into one another, corresponds here to the direction of movement 2 of the assembly movement, which in turn is defined by the longitudinal extension directions of bore 13 and pin 23. Plugging the plug connection elements 40, 41 into one another serves to create at least one electrically conductive plug connection for the purpose of implementing a respective electrical connection between the electrical rotary machines of the machine unit 10 and the control electronics of the power electronics 20.

[0052] The longitudinal extension of the pin 23 is longer than the longitudinal extension of a respective plug connection element 41 of the electronics housing 21, so that the pin 23 is inserted into the bore 13 in the assembly step shown here before the plug connection elements 41 of the electronics housing 21 are inserted into the plug connection elements of the machine housing 11, whereby the pin 23 in the bore 13 acts as a guide along the direction of movement 2 of the assembly movement.

[0053] In addition, Figure 2 shown that a seal 31 in the form of an O-ring is arranged on the pin 23, and that a tolerance sleeve 30 is arranged radially between the pin 23 and the bore 13 in such a way that it realizes an electrical contact between the bore 13 and the pin 23 when the pin 23 is inserted into the bore 13.

[0054] In Fig. 3a sectional side view of the electric drive device 1 is shown.

[0055] The power electronics 20 is arranged here on the machine unit 10 and the cutting plane runs parallel to the direction of movement of the assembly movement through bore 13 and pin 23.

[0056] In addition to Figure 2 It can be seen that the projection 22 is realized in such a way that the pin 23 is fixedly arranged as a separate component in an opening 26 in the electronics housing 21 of the power electronics 20.

[0057] The pin 23 comprises a first pin section 24 and a second pin section 25 and the bore 13 comprises a first bore section 14 and a second bore section 15.

[0058] The diameter of the first pin portion 24 is larger than the diameter of the second pin portion 25. The diameter of the first bore portion 14 is larger than the diameter of the second bore portion 15.

[0059] The diameter of the first pin section 24 essentially corresponds to the diameter of the opening 26. The diameter of the second pin section 25 essentially corresponds to the diameter of the second bore section 15. The pin 23 is arranged with its first pin section 24 partially in the opening 26 in the electronics housing 21 and partially in the first bore section 14. The pin 23 is arranged with its second pin section 25 in the second bore section 15.

[0060] However, the diameter of the first bore section 14 is larger than the diameter of the first pin section 24, wherein the tolerance sleeve 30 is arranged perpendicular to the direction of movement of the assembly movement between the first bore section 14 and the first pin section 24.

[0061] The tolerance sleeve 30 serves to bridge the distance between the first pin section 24 and the first bore section 14 and to support positioning and electrical contact between the pin 23 and the bore 13. The seal 31, designed as an O-ring, is arranged on the first pin section 24 such that it is arranged along the direction of movement of the assembly movement between the part of the electronics housing 21 forming the opening 26 and the part of the machine housing 11 forming the recess 12, thus sealing the plug connection between the pin 23 and the bore 13 against the environment.

[0062] The material forming the pin 23 and the bore 13 is designed to be electrically conductive at least in sections, so that by inserting the pin 23 into the bore 13 and thus creating an electrically conductive connection between the pin 23 and the bore 13, the power electronics 20 is grounded via the grounded machine unit 10 or the machine unit 10 is grounded via the grounded power electronics 20.

[0063] With the electric drive device according to the invention and the drive arrangement equipped therewith, the electromagnetic compatibility can be increased cost-effectively. List of reference symbols

[0064] 1Electric drive device 2Direction of movement of the assembly movement 10Machine unit 11Machine housing 12Recess 13Bore 14First bore section 15Second bore section 16Connection side of the machine housing 17Hub 18Top of the machine housing 20Power electronics 21Electronics housing 22Protrusion 23Pin 24First pin section 25Second pin section 26Opening 27Connecting flange 28Connection side of the electronics housing 30Tolerance sleeve 31Seal 40Connection direction 41Connection element of the electronics housing 42Form element of the electronics housing 43Form element of the machine housing

Claims

1. An electrical drive device (1), comprising a machine unit (10) having a machine housing (11) and at least one electrical rotary machine arranged therein, and comprising power electronics (20) having an electronics housing (21) and control electronics arranged therein, wherein at least one of the two housings has at least one protrusion (22) for defined positioning of the machine unit (10) and the power electronics (20) against one another during and / or after assembly, and the respective other housing (11, 21) has a complementary cut-out (12) in shape and size for receiving the protrusion (22), wherein material forming the protrusion (22) and the cut-out (12) is electrically conductive at least in sections, and the protrusion (22) and the cut-out (12) are electrically conductively connected to an earth for the purpose of earthing the power electronics (20) or the machine unit (10), and the protrusion (22) has the shape of a pin (23) and the cut-out (12) has the shape of a bore (13), in which the pin (23) is received, characterised in that an electrically conductive tolerance sleeve (30) is arranged between the pin (23) and the bore (13) for bridging the distance between the pin (23) and the bore (13).

2. The electrical drive device (1) according to claim 1, characterised in that the machine unit (10) has an earth and the power electronics (20) are also earthed via the electrically conductive connection and the machine unit (10).

3. The electrical drive device (1) according to one of the preceding claims, characterised in that the protrusion (22) is formed on the electronics housing (21) and the cut-out (13) is formed in the machine housing (11).

4. The electrical drive device (1) according to claim 1, characterised in that the pin (23) is seated in the bore (13) with an interference fit.

5. The electrical drive device (1) according to one of the preceding claims, characterised in that a seal (31) is arranged between the two housings (11, 21).

6. The electrical drive device (1) according to one of claims 1 to 5, characterised in that plug-in connection elements (41) are arranged on both housings (11, 21), which plug-in elements are designed to be plugged into one another along a plug-in connection direction (40) to form at least one electrically conductive plug-in connection for realising a respective electrical connection between the machine unit (10) and the power electronics (20), wherein the plug-in connection direction (40) runs parallel to the longitudinal extension direction of the pin (23).

7. The electrical drive device (1) according to one of the preceding claims, characterised in that the material of the machine housing (11) and / or the electronics housing (21) is i) an aluminium alloy, or ii) a magnesium alloy.

8. A drive assembly having an electrical drive device (1) according to one of claims 1 to 7 and having an internal combustion engine, which is or can be coupled in a non-rotatable manner to a rotor of the first electrical rotary machine.