Power converter for a vehicle and method for producing a power converter

Abstract

Power converter (108) for a vehicle (100), wherein the power converter (108) has the following features: a transistor unit (112); a power converter housing (118) with a cooling unit (116) arranged on or in the power converter housing (118) for dissipating heat from the transistor unit (112), wherein the cooling unit (116) and the transistor unit (112) are connectable or connected to one another in a planar manner; and an at least partially resilient holding unit (120, 120') for holding the transistor unit (112) in the power converter (108), wherein the holding unit (120, 120') is designed to press the transistor unit (112) flat against the cooling unit (116), wherein the holding unit (120, 120') is connectable or connected in a form-fitting manner to the transistor unit (112) or to the power converter housing (118), characterized in that the transistor unit (112) has at least one clamping opening (1900, 1900') into which the holding unit (120, 120') is inserted or can be inserted in order to clamp the transistor unit (112) to the cooling unit (116), wherein the clamping opening (1900, 1900') extends in a plane with a printed circuit board (1902) of the transistor unit (112).

Description

[0001] The present invention relates to a power converter for a vehicle, to an electric axle drive and to a method for producing a power converter.

[0002] Power converters are used in many different areas and for different devices or machines, such as in connection with e-mobility, which is becoming increasingly important today.

[0003] Fastening devices for electrical components are known from US 2018 / 0 343 775 A1, DE 103 17 182 A1 and DE 42 18 224 A1.

[0004] Against this background, the present invention provides an improved power converter for a vehicle, an improved electric axle drive, and an improved method for manufacturing a power converter according to the independent claims. Advantageous embodiments emerge from the subclaims and the following description.

[0005] The approach presented here, for example, creates a way to maximize the available space within a power converter. This includes, in particular, creating as much space as possible for a variety of electrical components, thus improving volume utilization, electrical contact, and thermal integration. Depending on the design, the size or dimensions of the power converter can also be advantageously reduced.

[0006] A power converter for a vehicle is presented, wherein the power converter has a transistor unit. Furthermore, the power converter has a power converter housing with a cooling unit arranged on or in the power converter housing for dissipating heat from the transistor unit, wherein the cooling unit and the transistor unit can be connected or are connected to one another in a planar manner, and an at least partially resilient holding unit for holding the transistor unit in the power converter, wherein the holding unit is designed to press the transistor unit flatly against the cooling unit. The holding unit can be connected or are connected in a form-fitting manner to the transistor housing or to the power converter housing. The power converter can advantageously be used in a vehicle that can be designed as a passenger car, a commercial vehicle, or a truck. Furthermore, the vehicle can be electrically powered.The power converter can be designed, for example, as an inverter or as a DC-DC converter. The transistor unit can be designed, for example, as a component of the power converter. The transistor unit can have a printed circuit board and a transistor housing for enclosing the printed circuit board. Advantageously, the compactly implemented transistor unit can be easily inserted into the power converter from above, without the need for additional fixing means, such as screws or other types of fastening of the spring element. The transistor housing can, for example, have at least one housing element or, alternatively, can be implemented, for example, by encasing the printed circuit board with, for example, an injection-molded material.The circuit board surrounded by the transistor housing can, for example, have at least one electrical line that can be designed to electrically connect the transistor unit within the power converter, for example to another circuit board. The line can, for example, be led through a recess in the transistor housing, which can, for example, be made of plastic. The transistor unit can, for example, be or become attached to the power converter housing, more precisely to the cooling unit, which can, for example, be designed as a cooling wall. For example, the cooling unit can have a cooling channel through which a cooling fluid can be passed. The holding unit can, for example, be designed in one part or in multiple parts. Advantageously, the holding unit can be or become attached at one end to the transistor unit or to the power converter housing.By using the holding unit, which is designed, for example, as a spring element, the transistor unit can be advantageously pressed flat against the surface. This is particularly advantageous when mounted from above. This also means that the voltage can be built up, for example, via a bias voltage or when the transistor unit is installed in the power converter.

[0007] The transistor unit has at least one clamping opening into which the holding unit can be inserted or plugged in order to clamp the transistor unit to the cooling unit. The clamping opening can extend in a plane with a circuit board of the transistor unit. The insertion direction of the holding unit can therefore run along a profile of the plane of the circuit board. The clamping opening can be designed, for example, as a through-opening that extends completely through the transistor unit or a transistor housing of the transistor unit. This advantageously allows the transistor unit to be connected to the cooling unit in a force-fitting and form-fitting manner.

[0008] According to one embodiment, the holding unit can be shaped as at least one spring clip, in particular L-shaped or U-shaped. Advantageously, the holding unit can have rounded corners or bent sections. In a U-shaped implementation, the holding unit can, for example, have two side sections and a central section arranged between the side sections and can therefore advantageously encompass the transistor unit on three sides and thereby hold it to the cooling unit. As an L-shaped holding unit, it can, for example, contact two adjacent side surfaces of the transistor unit. Advantageously, a snap mechanism of the holding unit can be triggered upon or by inserting the transistor unit.

[0009] In an embodiment not according to the invention, the power converter housing can have at least one retaining wall adjacent to the cooling unit, said retaining wall having a projection for positive connection to the retaining unit. Advantageously, the transistor unit can thereby be pressed against the cooling unit by means of a clamping force. The retaining wall can, for example, be aligned transversely to the cooling unit, i.e., transversely to a contact surface of the cooling unit against which the transistor unit is pressed. Advantageously, the power converter housing can have two retaining walls arranged parallel to one another, both of which can have such a projection for positive connection to the retaining unit. The projections can be arranged on mutually facing sides of the retaining walls.

[0010] The holding unit can have at least one latching hook for latching into the projection and at least one spring arm for bearing against the transistor unit. The at least one latching hook can advantageously be arranged at a free end of a U-shaped holding unit. For example, the holding unit can have two side sections and a central section arranged between the side sections, so that, for example, a latching hook can be arranged on each of the side sections. On or in the central section, the at least one spring arm can press the transistor unit against the cooling unit, i.e. be non-positively connected to it and connect it non-positively to the cooling unit.

[0011] According to one embodiment, the power converter housing can have at least one retaining pin on a bottom surface of the power converter housing, which can be shaped to engage the retaining unit and additionally or alternatively the transistor unit. The retaining pin can also be referred to as a retaining pin. The retaining pin can be firmly embedded in the bottom surface. For example, the retaining pin and the bottom surface can be designed as a single piece to hold the transistor unit in its position with a positive fit.

[0012] In an embodiment not according to the invention, the transistor unit can have a receiving opening for receiving the holding pin in a side wall facing the bottom surface. The holding unit can have a latching opening for receiving the holding pin and a lug adjacent to the latching opening for engaging in the receiving opening. Advantageously, the holding pin can engage in the receiving opening through the latching opening, whereby a lateral displacement of the holding unit occurs. The displacement can advantageously occur by placing it on the holding pin. The receiving opening and the latching opening can advantageously be arranged so as to at least partially overlap and additionally or alternatively have the same or at least approximately the same dimensions. The lug can advantageously prevent the holding unit from slipping relative to the transistor unit before assembly.

[0013] In an embodiment not according to the invention, the retaining pin can have at least one guide surface, which can be inclined relative to the base surface. The guide surface can be designed to cause a displacement of the retaining unit relative to the converter housing to build up spring tension. The guide surface can cause the lateral displacement of the retaining unit, thereby building up a clamping force for the frictional connection, by which the transistor unit can be pressed against the cooling unit. Thus, for example, secure assembly of the transistor unit can be advantageously simplified.

[0014] According to one embodiment, the holding unit inserted into the clamping opening can rest against the converter housing on a side of the cooling unit facing away from the transistor unit and / or be encapsulated using a potting material. The potting material can advantageously prevent the holding unit and, additionally or alternatively, the transistor unit from slipping out or becoming loose. More specifically, their position can advantageously be fixed.

[0015] The power converter can also have a heat-conducting unit for thermally coupling the transistor unit and the cooling unit, wherein the heat-conducting unit can be arranged between the transistor unit and the cooling unit. The heat-conducting unit can, for example, be designed as a layered composite with at least one layer. For example, the heat-conducting unit can be designed to be both thermally conductive and electrically insulating.

[0016] In an embodiment not according to the invention, the holding unit can have a fixing section at one end for fixing the holding unit to the power converter housing and a clamping section for clamping the transistor unit to the cooling unit at an end remote from the fixing section. The holding unit can be moved from a first preferred position to a second preferred position in order to pretension the holding unit. The holding unit can be moved from the second preferred position to a first preferred position in order to clamp the transistor unit to the cooling unit. The clamping sections can, for example, be arranged such that the holding unit is L-shaped. When fixing the holding unit to the power converter housing, a positive connection can advantageously be established.Advantageously, the holding unit in the second preferred position can form a trigger in the fixing section that can be actuated by the transistor unit in order to transfer the holding unit from the second preferred position to the first preferred position.

[0017] The invention also relates to an electric axle drive for a motor vehicle comprising at least one electric motor, a transmission device, and a power converter. The electric axle drive is characterized in that the power converter is designed as described. The transmission device can comprise a gear for reducing the speed of the electric motor and a differential.

[0018] The invention also relates to a motor vehicle with an electric axle drive and / or a power converter. The motor vehicle is characterized in that the electric axle drive and / or the power converter are designed as described.

[0019] A method for producing a power converter in a variant mentioned above comprises a step of fixing the transistor unit to the cooling unit using the holding unit to press the transistor unit flatly against the cooling unit, wherein the holding unit is positively connected to the transistor unit or to the power converter housing.

[0020] Advantageously, the method can be used to assemble or mount an embodiment of the power unit mentioned herein. For example, a joining process for the transistor unit can also be performed or controlled within the scope of the method for manufacturing the power converter in order to produce the transistor unit. Advantageously, the transistor unit can thereby be fixed vertically to the cooling unit with respect to a power converter base of the power converter, for example, by a holding unit.

[0021] According to one embodiment, the method can comprise a step of positioning the transistor unit on the cooling unit prior to the fixing step, wherein, in the fixing step, spring tension of the holding unit can be applied in order to press the transistor unit flat against the cooling unit. For example, before fixing, the holding unit can be pretensioned, and by inserting the transistor unit, a trigger can be actuated, for example, to apply the spring tension and press or press the transistor unit against the cooling unit. The transistor unit can be aligned vertically relative to a power converter base and thus pressed flat against the cooling unit. Additionally or optionally, the holding unit can be fixed to the cooling unit using a potting material, for example. This can advantageously prevent slipping of the transistor unit and, additionally or optionally, of the holding unit.

[0022] The invention is explained in more detail by way of example with reference to the accompanying drawings. They show: Fig. 1 a schematic representation of a motor vehicle according to an embodiment; Fig. 2 to 17 are schematic representations of embodiments not according to the invention of a holding unit of a power converter; Fig. 18 to 21 are schematic representations of embodiments of a holding unit of a power converter; and Fig. 22 is a flowchart of a method for manufacturing a power converter for a vehicle.

[0023] In the following description of preferred embodiments of the present invention, the same or similar reference numerals are used for the elements shown in the various figures and having a similar effect, whereby a repeated description of these elements is omitted.

[0024] To better understand the context of the approach, a brief overview of the topic is provided first. Power transistors are frequently used in converters, such as DC / DC converters and onboard chargers. There are various designs available, differing in the type of connection pins and cooling surfaces. A fundamental goal here is to fill the available installation space as optimally as possible and to maximize power density. The size of the installation space is largely determined by other passive components, such as chokes, transformers, or capacitors. According to exemplary embodiments, the aforementioned goal of optimizing installation space utilization and power density can be advantageously achieved.

[0025] Fig. 1 shows a schematic representation of a motor vehicle 100 according to an exemplary embodiment. The motor vehicle 100 is also referred to as a vehicle, for example. The motor vehicle 100 has an electric axle drive 102, which in turn has at least one electric machine 104, a transmission device 106, and a power converter 108. Overall, the motor vehicle 100 is designed, for example, as a passenger car.

[0026] The electric machine 104 is also referred to, for example, as a drive unit or as an electric motor and is coupled, for example, to the transmission device 106. The motor vehicle 100 further comprises a power supply device 110, which is referred to, for example, as a battery. According to this exemplary embodiment, the power converter 108 is connected between the power supply device 110 and the electric machine 104.

[0027] The power converter 108 has a transistor unit 112, for example with a circuit board and a transistor housing for enclosing the circuit board. The power converter 108 also has a cooling unit 116. The cooling unit 116 is designed to dissipate heat from the transistor unit 112, wherein the cooling unit 116 and the transistor unit 112 are connectable or connected to one another in a planar manner. The power converter 108 also has a power converter housing 118, wherein the cooling unit 116 is arranged in or on the power converter housing 118. The cooling unit 116 is therefore formed, for example, as a housing part of the power converter housing 118 or integrated into the power converter housing 118. The transistor unit 112 is arranged in the power converter housing 118. The transistor unit 112 is referred to, for example, as a Vertical Power Package (VPP).Furthermore, the power converter 108 has an at least partially resilient holding unit 120 for holding the transistor unit 112 in the power converter 108, wherein the holding unit 120 is designed to press the transistor unit 112 flat against the cooling unit 116. The holding unit 120 is connectable or connected in a form-fitting manner to the transistor unit 112 or a transistor housing of the transistor unit 112 or to the power converter housing 118.

[0028] Furthermore, the power converter 108 optionally has a heat conduction unit 114. The heat conduction unit 114 is arranged between the transistor unit 112 and the cooling unit 116 in order to thermally couple the transistor unit 112 and the cooling unit 116 and to electrically insulate them from each other.

[0029] The power converter 108 additionally comprises, for example, a capacitor and a plurality of switches, for example, six in number. These components are combined, for example, as electrical components. The transistor unit 112 comprises, for example, a low-inductance commutation cell for power transistors, for example, through an integrated snubber capacitor, and enables, for example, driver integration as a prerequisite for the use of fast-switching power semiconductors made of, for example, silicon carbide (SiC) and / or gallium nitride (GaN). Electrical insulation from housing parts is achieved, for example, by plastic encapsulation.

[0030] Fig. 2 to 21 show a schematic representation of an embodiment of a holding unit of a power converter, as already described, for example, in Fig. 1. The holding unit 120 can be implemented in different ways, so that the individual design variants of the holding unit 120 are described in more detail in the following description. The function of the holding unit 120 consists in the following described Fig. 2 to 21 is to hold the transistor unit 112 in the power converter 108. More precisely, the holding unit 120 is designed to press the transistor unit 112 flat against the cooling unit 116, wherein the holding unit 120 can be connected or is connected in a form-fitting manner to the transistor unit 112 or its transistor housing or to the power converter housing 118. The holding unit 120 is designed, for example, as a spring clip that is L-shaped or U-shaped.

[0031] In Fig. 2 is a schematic representation of an embodiment of a holding unit 120, 120' of a power converter, such as can be incorporated into a power converter according to Fig. 1 is used or usable. Here, a section 200 of the power converter is shown in order to depict a contact area in which the transistor unit 112 contacts the cooling unit 116. The holding unit 120, 120' is L-shaped according to this exemplary embodiment in order to implement, for example, a snap mechanism that can be triggered by the transistor unit. More precisely, the holding unit 120, 120' according to this exemplary embodiment comprises two L-shaped spring clips. For this purpose, the holding unit 120, 120' has a fixing section 202 at one end for fixing the holding unit 120, 120' to the power converter housing 118 and a clamping section 204 at an end facing away from the fixing section 202 for clamping the transistor unit 112 to the cooling unit 116. The clamping section 204 presses, for example, against the transistor unit 112 or the transistor housing 206 of the transistor unit 112.

[0032] The holding unit 120, 120' can be transferred from a first preferred position 207 into a second preferred position in order to pre-tension the holding unit 120, 120'. However, this is done in at least one of the Fig. 3 to 7. The preferred positions differ, for example, in the position of the clamping section 204 relative to the fixing section 202 and thus the clamping force acting on the transistor unit 112. In Fig. 2, the holding unit 120, 120' is shown in the first preferred position 207 and the transistor unit 112 is thus clamped. The same is positively connected to the cooling unit 116. The fixing section 202 is connected to a bottom surface 208 of the power converter housing 118 or, for example, fixed to it in such a way that the holding unit 120, 120' in the fixing section 202 forms the trigger for the snap mechanism in the second preferred position, as is shown, for example, in Fig. 4, to transfer the holding unit 120 from the second preferred position to the first preferred position 207. Alternatively, the holding unit 120, 120' can also be transferred, for example, manually by a user from the second preferred position to the first preferred position 207.

[0033] In other words, the holding unit 120, 120' described here allows for two preferred positions and a clamping mechanism. The holding unit 120, 120', as a clamp, is tensioned, for example, and hooked into the power converter housing 118. The transistor unit 112, which is also referred to as a power transistor, is inserted and, according to this embodiment, actuates the release mechanism, so that the holding unit 120, 120' presses the transistor unit 112 against the cooling unit 116, thereby enabling a thermal connection.

[0034] In Fig. 3 is a schematic representation of an embodiment of a holding unit 120 of a power converter, which, for example, corresponds to the one shown in Fig. 2 described holding unit. In Fig. 3, the section 200 of the power converter is rotated to the one shown in Fig. 2. The fixing section 202 of the holding unit 120 is shown here hooked into the base surface 208.

[0035] In Fig. 4 also shows a schematic representation of an embodiment of a holding unit 120 of a power converter, which, for example, corresponds to the one shown in the Fig. 2 and Fig. 3. Here, the holding unit 120 is shown in the second preferred position 400. This means that the clamping section 204 is preloaded and thus the transistor unit 112 can be inserted. Preloaded in the second preferred position 400, the holding unit 120 forms a trigger 402 in the fixing section 202, which can be actuated, for example—as shown here—by inserting the transistor unit 112. In response to the actuation of the trigger 402, the clamping section 204 snaps shut, reaching the first preferred position, and presses the transistor unit 112 against the cooling unit 116.

[0036] In Fig. 5 is also a schematic representation of an embodiment of a holding unit 120 of a power converter, which, for example, corresponds to the one shown in the Fig. 2 to 4. The cutout 200 is shown in a side view, showing the first preferred position.

[0037] In Fig. 6 is a schematic representation of an embodiment of a holding unit 120, 120' of a power converter, which, for example, corresponds to the one shown in the Fig. 2 to 5. Here, the holding unit 120, 120' is similar to that in Fig. 4 in the second preferred position 400. In Fig. However, the transistor unit is not shown in Figure 6. This means that Fig. 6 may be an assembly snapshot. The trigger 402 is also molded here.

[0038] In Fig. 7, the holding unit 120, 120' is as in Fig. 6, but shown rotated. This means that the Fig. 7 shown holding unit 120, 120' of the Fig. 6 and differs only in the perspective of the display.

[0039] Fig. Figure 8 shows a schematic representation of an embodiment of a holding unit 120, 120' of a power converter and is similar, for example, to that shown in at least one of the Fig. 1 to 7. Also according to the Fig. In the embodiment shown in Figure 8, the holding unit 120 is L-shaped. Here, the holding unit 120, 120' is connected to the transistor unit 112 before it is coupled to the power converter housing 118. For this purpose, the power converter housing 118 has at least one holding pin 800 on the bottom surface 208, which is also referred to, for example, as the housing bottom. According to this embodiment, two holding pins 800, 802 are arranged on the bottom surface 208, which have, for example, a square basic shape or, alternatively, a triangular or round basic shape. Their free ends are, for example, rounded or flattened. Furthermore, the holding pins 800, 802 can also be referred to as pins. The holding pin(s) 800, 802 are shaped to engage in the holding unit 120, 120' and / or the transistor unit 112 or the transistor housing 206. This creates a positive connection.

[0040] The transistor unit 112 or the transistor housing 206 has at least one receiving opening 806 in a side wall 804 facing the bottom surface 208, which is shaped to receive the retaining pin 800 according to this exemplary embodiment. The retaining unit 120 has a latching opening 808 for receiving or inserting the retaining pin 800, which is arranged to at least partially overlap the receiving opening 806 when the retaining unit 120 is connected to the transistor unit 112. The retaining unit 120 further has a lug 810 adjacent to the latching opening 808, which is designed to engage in the receiving opening 806. The engagement of the lug 810 in the receiving opening 806 and of the retaining pin 800 in the latching opening 808 and the receiving opening 806 fixes the transistor unit 112 in its position.The holding unit 120, 120' is designed as at least one spring clamp and, according to this exemplary embodiment, also comprises a second spring clamp of the same design, so that all described features refer to both spring clamps.

[0041] More precisely, this means that the transistor unit 112 or the transistor housing 206 has a further receiving opening 806' in the side wall 804, which is shaped to receive the retaining pin 802 according to this exemplary embodiment. The retaining unit 120' has a latching opening 808' for receiving the retaining pin 802, which is arranged to at least partially overlap the receiving opening 806'. The retaining unit 120' further has a nose 810' adjacent to the latching opening 808', which is designed to engage in the receiving opening 806'. The engagement of the nose 810' in the receiving opening 806' and of the retaining pin 802 in the latching opening 808' and the receiving opening 806' fixes the transistor unit 112 in its position.

[0042] The holding unit 120, 120' is shaped to press the transistor unit 112 against the cooling unit 116 in an assembled state and thus to establish a force-locking connection.

[0043] In other words, the holding unit 120, 120' is hooked onto the transistor unit 112 or the transistor housing 206 by the lugs 810, 810'. The holding pins 800, 802 are, for example, square and are inserted into the transistor unit 112 or the transistor housing 206. By means of a bevel, which is Fig. 10 as a guide surface, the holding unit 120, 120' is displaced laterally and a spring tension is built up in order to press the transistor unit 112 firmly onto the cooling unit 116 designed as a cooling wall.

[0044] In Fig. 9 is also a schematic representation of an embodiment of a holding unit 120, 120', which, for example, corresponds to the one shown in Fig. 8 described holding unit. In contrast to Fig. 9, the individual components, i.e., the transistor unit 112 and the holding unit 120, 120', are arranged on the heat sink 116 and thus shown assembled. The holding unit 120, 120' presses the transistor unit 112 against the cooling unit 116. In Fig. 10 also shows a schematic representation of an embodiment of a holding unit 120 of a power converter, as is also shown, for example, in at least one of the Fig. 8 to 9. Here is the Fig. 8, the lug 810 mentioned above is shown again, which engages in the receiving opening 806 of the transistor unit 112 or the transistor housing 206. To ensure that the fixing section 202 of the holding unit 120 remains laterally displaceable in the direction of the cooling unit 116, the lug 810 is designed to be smaller than an edge of the transistor unit 112 or the transistor housing 206 surrounding the receiving opening 806.

[0045] In order to cause the holding unit 120 to be displaced relative to the power converter housing 118 in order to build up spring tension, the holding pin 800 according to this exemplary embodiment has at least one guide surface 1000 that is inclined relative to the base surface 208. For example, the holding pin 800 has a plurality of guide surfaces that can be of different lengths or can be realized at an angle. The displacement of the holding unit 120 occurs, for example, during insertion of the transistor unit 112 into the power converter housing 118, in that the holding pin 800, with the at least one guide surface 1000, guides the holding unit 120 on an edge of the holding unit 120 surrounding the latching opening 808.

[0046] Fig. 11 shows a schematic representation of an embodiment of a holding unit 120 of a power converter, which, for example, corresponds to the holding unit in Fig. 8 to Fig. 10. In Fig. 11 the coupling point is shown only enlarged.

[0047] Fig. 12 shows a schematic representation of an embodiment of a holding unit 120 of a power converter, which in at least one of the Fig. 8 to 11. Here, the transistor unit 112 is connected to the cooling unit 116 in a planar manner. The retaining pin 800, together with the fixing section 202 of the retaining unit 120 and the transistor unit 112, enables a positive connection, and the clamping section 204 enables a non-positive connection.

[0048] Fig. 13 shows a schematic sectional view of an embodiment of a holding unit 120 of a power converter, as shown for example in the Fig. 8 to 12. More precisely, the positive connection of the holding unit 120 with the power converter housing and the resulting force-locking and positive connection of the transistor unit 112 with the cooling unit 116 is shown enlarged, as shown, for example, in Fig. 12 was described.

[0049] Fig. 14 shows a schematic representation of an embodiment of a holding unit 120 of a power converter, as used for example in at least one of the Fig. 1 to 13 or at least mentioned. However, according to this exemplary embodiment, the holding unit 120 is U-shaped. The holding unit 120 has a central section 1400, which borders on two opposite sides a respective side section 1402, 1404. The holding unit 120 further has at least one latching hook 1406 and at least one spring arm 1408, 1409 for abutting against the transistor unit 112. A latching hook 1406 is arranged on each of the side sections 1402, 1404.

[0050] The power converter housing 118 has at least one retaining wall 1410 adjacent to the cooling unit 116 and, according to this exemplary embodiment, also a second retaining wall 1412, each of which has a projection 1414, 1416 for positive connection to the locking hooks 1406 of the retaining unit 120. The retaining walls 1410, 1412 are arranged transversely to the cooling unit 116 and, in particular, perpendicular to the cooling unit 116. The locking hook 1406 is designed to engage the projection 1414 and thereby achieve a positive connection. The at least one spring arm 1408, 1409 is designed to exert a clamping force on the transistor unit 112 and thereby press the transistor unit 112 against the cooling unit 116.

[0051] In other words, the holding unit 120 has at least one latching hook 1406 and at least one spring arm 1408, 1409. The latching hook(s) 1406 hook the holding unit 120 to the power converter housing 118, more precisely, to the at least one holding wall 1410. The spring structure with the spring arms 1408, 1409 presses the transistor unit 112 onto the cooling unit 116. The spring tension is built up when the latching hooks 1406 engage the projections 1414, 1416.

[0052] Fig. 15 shows a schematic representation of an embodiment of a holding unit 120 of a power converter, which, for example, corresponds to the one shown in Fig. 14 described holding unit. In Fig. 15, the holding unit 120 is shown only individually and not assembled.

[0053] Fig. 16 shows a schematic representation of an embodiment of a holding unit 120 of a power converter, as shown for example in the Fig. 14 and Fig. 15. Overall, the holding unit 120 is similar to the ones described in the Fig. 1 to 15 described holding units in their function. Like the holding units described previously, the one shown in Fig. 16 described holding unit 120 can be used for a power converter, as it is used for example in Fig. 1 was described.

[0054] According to this exemplary embodiment, the holding unit 120 is not yet coupled to the power converter housing 118 or shown spaced apart from it. However, an attachment direction is symbolically represented by an arrow to illustrate how the transistor unit 112 is fixed to the cooling unit 116. According to this exemplary embodiment, the holding walls 1410, 1412 each have a bevel 1618, 1620, which can also be referred to as a guide surface. The bevels 1618, 1620 are designed to guide the locking hook(s) 1406, 1600 along the projections 1414, 1416 until they engage. The spring arms 1408, 1409 exert a counterforce during assembly and also in the assembled state of the transistor unit 112, which presses the transistor unit 112 against the cooling unit 116, as is the case, for example, in Fig. 17 is shown.

[0055] Fig. 17 shows a schematic representation of an embodiment of a holding unit 120 of a power converter, which, for example, corresponds to the one shown in at least one of the Fig. 1 to 16 and in particular the holding unit described in the Fig. 14 to 16. The holding unit 120 holds the transistor unit 112 to the cooling unit 116 by means of frictional engagement. The holding unit 120 is positively connected to the cooling unit 116.

[0056] Fig. 18 shows a schematic representation of an embodiment of a holding unit 120, 120' of a power converter, which, for example, corresponds to the one shown in at least one of the Fig. 1 to 17. Here, the holding unit 120, 120' holds the transistor unit 112 to the cooling unit 116 by means of positive locking and frictional locking.

[0057] According to this embodiment, the holding unit 120, 120' is U-shaped and is clamped, for example, to the cooling unit 116. Due to its shape, the holding unit 120, 120' creates the positive connection. The non-positive connection is created by the holding unit 120, 120' in that it also Fig. 18 is realized as a spring clip, which comprises, for example, a metallic material. According to this exemplary embodiment, the holding unit 120, 120' is designed in two parts in order to fix the transistor unit 112 evenly and flatly with uniform clamping force to the cooling unit 116. For example, the holding unit 120, 120' is inserted into the transistor unit 112 or the transistor housing 206 of the transistor unit 112, as shown in the following Fig. 19 to 21. According to this exemplary embodiment, a heat conduction unit 114 is additionally arranged between the transistor unit 112 and the cooling unit 116 for thermally coupling the transistor unit 112 and the cooling unit 116.

[0058] Fig. 19 shows a schematic representation of an embodiment of a holding unit 120, 120' of a power converter, which, for example, corresponds to the one shown in at least one of the Fig. 1 to 18 and in particular the holding unit described in Fig. 18. This shows a method of attaching the holding unit 120, 120' to the cooling unit 116, or to the transistor unit 112. This means that a snapshot is shown here before the transistor unit 112 is connected to the cooling unit 116 by the holding unit 120, 120'.

[0059] To attach the holding unit 120, 120', the transistor unit 112 has, for example, on the transistor housing 206, at least one clamping opening 1900, 1900', into which the holding unit 120, 120' is inserted to clamp the transistor unit 112 to the cooling unit. The clamping opening 1900, 1900' extends in a plane with a circuit board 1902 of the transistor unit 112. According to this exemplary embodiment, the transistor unit 112 or the transistor housing 206 is wider in the region of the clamping openings 1900, 1900' than in the region of the circuit board 1902, for example to electrically insulate the circuit board 1902 and the holding unit 120, 120' from one another.

[0060] The heat conduction unit 114 is also in Fig. 19 is arranged between the transistor unit 112 and the cooling unit 116 to establish the thermal connection.

[0061] Fig. 20 shows a schematic representation of an embodiment of a holding unit 120 of a power converter, which, for example, corresponds to the one shown in at least one of the Fig. 18 to 19. More precisely, this is a partial sectional view to better illustrate the clamping opening 1900. The clamping opening 1900 is implemented as a through-opening in the transistor unit 112 or the transistor housing 206. The holding unit 120 rests against the power converter housing 118 on a side of the cooling unit 116 facing away from the transistor unit 120. Walls of the transistor unit 112 or the transistor housing 206 surrounding the clamping opening 1900 are, for example, reinforced, which has a positive effect on stability. At the level of the clamping opening 1900, the transistor unit 112 or the transistor housing 206 according to this exemplary embodiment has a rib-like surface structure 2000, which can, for example, assist in the dissipation of heat from the transistor unit 112.

[0062] The holding unit 120 is also available in Fig. 20 is formed as a U-shaped spring clip which, when inserted into the clamping opening 1900, enables both the positive connection and the non-positive connection between the transistor unit 112 and the cooling unit 116 or the heat conducting unit 114.

[0063] Fig. 21 shows a schematic representation of an embodiment of a holding unit 120 of a power converter, which in at least one of the Fig. 18 to 20 corresponds to or at least resembles the holding unit described. Fig. 21, the holding unit 120 inserted into the clamping opening rests against the converter housing 118 on a side of the cooling unit 116 facing away from the transistor unit 112 and is optionally additionally potted using a potting material 2100, thereby securing it in position. This prevents, for example, the holding unit 120 from slipping out or becoming loose.

[0064] In other words, the transistor unit 112 is placed on the cooling unit 116 to create a thermal connection. The holding unit 120, 120' is mounted vertically, for example, "from above," so that one end of the holding unit 120, 120' is inserted into a clamping opening of the transistor unit 112 on one side of the cooling unit 116, which is also referred to as a plastic holder, and is clamped to the cooling unit 116 on another side of the cooling unit 116. Potting material 2100 is optionally used to fix the holding unit 120, 120' and press the transistor unit 112 against the cooling unit 116. The spring tension is thus built up upon insertion.

[0065] Fig. 22 shows a flow diagram of a method 2200 for manufacturing a power converter for a vehicle, as described, for example, in Fig. 1. The power converter manufactured by the method 2200 corresponds or is similar, for example, to that described in at least one of the Fig. 1 to 21 mentioned power converters.

[0066] The method 2200 comprises a step 2202 of fixing the transistor unit to the cooling unit using the holding unit in order to press the transistor unit flat against the cooling unit. The holding unit is positively connected to the transistor unit 112 or its transistor housing or to the power converter housing. Optionally, the method 2200 comprises a step 2204 of positioning the transistor unit on the cooling unit before the fixing step, wherein, in the fixing step, spring tension is applied to the holding unit in order to press the transistor unit flat against the cooling unit. Further optionally, the holding unit is additionally fixed to the cooling unit using a potting material.

[0067] In other words, an assembly concept of a transistor unit for a power converter is described.

[0068] The exemplary embodiments described and shown in the figures are selected only as examples. Different exemplary embodiments can be combined with each other in their entirety or with regard to individual features. Furthermore, one exemplary embodiment can be supplemented by features of another exemplary embodiment.

[0069] Furthermore, method steps according to the invention can be repeated and carried out in a different order than that described.

[0070] If an embodiment comprises an “and / or” link between a first feature and a second feature, this can be read such that the embodiment according to one embodiment has both the first feature and the second feature and according to another embodiment has either only the first feature or only the second feature. Reference symbol 100 motor vehicles 102 electric axle drive 104 electric machine 106 Gearbox 108 power converters 110 Energy supply facility 112 Transistor unit 114 Heat conduction unit 116 Cooling unit 118 converter housing 120 holding unit 120' holding unit 200 excerpt 202 Fixing section 204 clamping section 206 transistor packages 207 first preferred position 208 floor area 400 second preferred position 402 trigger 800 retaining pin 802 retaining pin 804 side wall 806 receiving opening 806' recording aperture 808 Snap-in opening 808' snap-in opening 810 Nose 810' nose 1000 guide surface 1400 middle section 1402 page section 1404 page section 1406 locking hooks 1408 spring arm 1409 spring arm 1410 retaining wall 1412 second retaining wall 1414 Head Start 1416 lead 1600 locking hooks 1618 Slope 1620 slope 1900 clamp opening 1900' clamp opening 1902 circuit board 2000 surface structure 2100 potting material 2200 Method for manufacturing a power converter 2202 Step of fixing the transistor unit 2204 Step of positioning the transistor unit

Claims

[1] Power converter (108) for a vehicle (100), the power converter (108) having the following features: a transistor unit (112); a power converter housing (118) with a cooling unit (116) arranged on or in the power converter housing (118) for dissipating heat from the transistor unit (112), wherein the cooling unit (116) and the transistor unit (112) are connectable or connected to one another in a planar manner; and an at least partially resilient holding unit (120, 120') for holding the transistor unit (112) in the power converter (108), wherein the holding unit (120, 120') is designed to press the transistor unit (112) flat against the cooling unit (116), wherein the holding unit (120, 120') is connectable or connected in a form-fitting manner to the transistor unit (112) or to the power converter housing (118), characterized by , that the transistor unit (112) has at least one clamping opening (1900, 1900') into which the holding unit (120, 120') is inserted or can be inserted in order to clamp the transistor unit (112) to the cooling unit (116), wherein the clamping opening (1900, 1900') extends in a plane with a printed circuit board (1902) of the transistor unit (112). [2] Power converter (108) according to claim 1, wherein the holding unit (120, 120') is formed as at least one spring clip, in particular L-shaped or U-shaped. [3] Power converter (108) according to one of the preceding claims, wherein the power converter housing (118) has at least one retaining pin (800, 802) on a bottom surface (208) of the power converter housing (118) which is shaped to engage the transistor unit (112). [4] Power converter (108) according to one of the preceding claims, wherein the holding unit (120, 120') inserted into the clamping opening (1900, 1900') rests on the power converter housing (118) on a side of the cooling unit (116) facing away from the transistor unit (112) and / or is potted by means of a potting material (2100). [5] Power converter (108) according to one of the preceding claims, comprising a heat conducting unit (114) for thermally coupling the transistor unit (112) and the cooling unit (116), wherein the heat conducting unit (114) is arranged between the transistor unit (112) and the cooling unit (116). [6] Electric axle drive (102) for a motor vehicle (100) with at least one electric machine (104), a transmission device (106) and a power converter (108), characterized by that the power converter (108) is designed according to one of the preceding claims. [7] Motor vehicle (100) comprising an electric axle drive (102) according to claim 6 and / or a power converter (108) according to one of claims 1 to 5. [8] A method (2200) for manufacturing a power converter (108) according to any one of claims 1 to 5, wherein the method (2200) comprises the following step: Fixing (2202) the transistor unit (112) to the cooling unit (116) using the holding unit (120, 120') in order to press the transistor unit (112) flat against the cooling unit (116), wherein the holding unit (120, 120') is positively connected to the transistor unit (112) or to the power converter housing (118). [9] Method (2200) according to claim 8, comprising a step (2204) of positioning the transistor unit (112) on the cooling unit (116) before the step (2202) of fixing, wherein in the step (2202) of fixing a spring tension of the holding unit (120, 120') is effected in order to press the transistor unit (112) flat against the cooling unit (116).

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