Transmission for a motor vehicle

Abstract

Transmission (G) for a motor vehicle, wherein the transmission (G) comprises a housing (GG), a gear set (RS) arranged within the housing (GG) for forming multiple gears between a drive shaft (GW1) and an output shaft (GW2) of the transmission (G), an electric machine (EM) operatively connected to the drive shaft (GW1), the output shaft (GW2) or an element (RSx) of the gear set (RS), and a power electronics module (LE). - wherein the power electronics module (LE) comprises a carrier element (S) with an inside (SI) and an outside (SA), a DC voltage connection (DC), an inverter (INV) and an AC voltage connection (AC) connected to a phase interface (AC2) of the electric machine (EM), - wherein the housing (GG) has an area (GGE) on an outer wall (GGA) for receiving the power electronics module (LE), which can be closed by the carrier element (S) of the power electronics module (LE), - wherein the area (GGE) of the housing (GG) and the inside (SI) of the support element (S) form a dry space (TR) for receiving the inverter (INV) which is attached to the support element (S), and - wherein the area (GGE) of the housing (GG) separates at least section by section the wheelset (RS) from the dry room (TR), characterized in that the area (GGE) for receiving the power electronics module (LE) is located between a lower edge (UK) of the gearbox housing (GG) and half a height (GH2) of the gearbox housing (GG), wherein the area (GGE) extends at least section by section above the lower third (GH3) of the height (GH) of the gearbox housing (GG), wherein at least a part of the AC voltage connection (AC) is arranged in that section of the power electronics module (LE) which extends above the lower third (GH3) of the height (GH) of the gearbox housing (GG).

Description

[0001] The invention relates to a transmission for a motor vehicle, as well as a motor vehicle with such a transmission. Here, a transmission refers in particular to a multi-speed transmission in which a plurality of gears, i.e., fixed gear ratios between an input shaft and an output shaft of the transmission, can be selected, preferably automatically, by means of switching elements. These switching elements are, for example, clutches or brakes. Such transmissions are primarily used in motor vehicles to adapt the speed and torque output characteristics of the drive unit to the vehicle's driving resistances in a suitable manner.

[0002] The applicant's patent application DE 10 2010 002 746 A1 describes such a transmission, which includes an electric machine arranged within a bell housing of the transmission. The electric machine is coupled to associated power electronics, the power electronics being provided in a cover structure of the transmission housing and connected to the electric machine via a phase interface. The cover structure is detachably attached to the transmission housing radially below the electric machine in the area of ​​the bell housing. This type of connection of the power electronics reduces the ground clearance of a motor vehicle equipped with such a transmission.

[0003] DE 11 2009 000 022 T5 discloses a hybrid drive device with a main body housing which has a connection area connected to an internal combustion engine and which incorporates a rotating electric machine.

[0004] In DE 11 2014 001 863 T5 describes a vehicle drive device which has an input component that is coupled to an internal combustion engine in a driveable manner.

[0005] It is therefore an object of the invention to further develop the transmission known in the prior art in such a way that the transmission has a compact height without significantly increasing the external dimensions of the transmission.

[0006] The problem is solved by the features of claim 1. Advantageous embodiments are shown in the dependent claims, the description and the figures.

[0007] The gearbox comprises a housing, a gear set arranged within the housing to form multiple gears between an input shaft and an output shaft of the gearbox, an electric motor, and a power electronics module. The electric motor is operatively connected to the input shaft, the output shaft, or to an element of the gear set.

[0008] The power electronics module comprises a carrier element with an inner and an outer surface, a DC voltage connection, an inverter, and an AC voltage connection. The AC voltage connection is connected to a phase interface of the electric machine, preferably via a detachable connection.

[0009] The housing has an area on one outer wall for accommodating the power electronics module. This area can be closed off by the mounting element of the power electronics module. The outer wall of the housing and the inside of the mounting element form a dry compartment in which the inverter is housed. The inverter is attached to the mounting element. The area of ​​the housing where the power electronics module is mounted separates, at least partially, the gear set of the gearbox from the dry compartment of the inverter.

[0010] The interaction of the gearbox housing and the mounting element for the power electronics module eliminates the need for a separate housing for the power electronics module. By creating a dry space within the wheelset area, the available installation space can be used particularly efficiently. This is because the wheelset often has a round, or at least rounded, cross-section, which is smaller than the cross-section of the electric motor. Therefore, by utilizing the installation space within the wheelset area for the power electronics module, the overall cross-section of the gearbox increases only slightly.

[0011] Preferably, the power electronics module is arranged laterally on the transmission. "Laterally" in this context means that the power electronics are not located above or below the transmission housing, but rather on an outer surface of the transmission housing. In a transmission for a vehicle powertrain oriented parallel to the direction of travel, the power electronics module is thus oriented towards one side of the vehicle.

[0012] According to a preferred embodiment, the transmission has an input shaft interface and an output shaft interface. Power can be transmitted from an external drive unit to the transmission's input shaft via the input shaft interface, optionally by engaging a disconnect clutch or a starting clutch. Power can be transmitted from the output shaft to the drive wheels of a motor vehicle equipped with the transmission via the output shaft interface. The power path between the output shaft and the drive wheels can include one or more differential gears as well as additional drive shafts. The input interface and the output interface are located at opposite ends of the transmission. The power electronics module is located between the input interface and the output interface and extends at least partially to above the lower third of the transmission housing's height.The term "installation height" here refers to the vertical dimension of the gearbox housing in its installed position in the motor vehicle.

[0013] The housing area for the power electronics module is located between a lower edge of the gearbox housing and half the gearbox housing's height. This housing area extends above the lower third of the gearbox housing's height. In this configuration, at least part of the AC voltage connection is located in that section of the power electronics module which extends above the lower third of the gearbox housing's height.

[0014] Preferably, the power electronics module has a section height that is less than one-third the height of the gearbox housing. In such a configuration, the DC voltage connection can be located in that section of the power electronics module which has a height that is less than one-third the height of the gearbox housing.

[0015] According to a preferred embodiment, the power electronics module extends predominantly along the lower third of the transmission housing's height. In other words, a large part of the power electronics module is arranged along the lower third of the transmission housing. This ensures that the interior space of a vehicle with such a transmission is not reduced.

[0016] Preferably, the support element has openings that can be closed by means of one or more covers. These openings allow assembly and / or maintenance work on the gearbox without having to detach the power electronics module from the gearbox. For example, the AC voltage connection can be located on the inside of the support element, with the AC voltage connection being accessible through the openings from an outside of the support element. This allows the AC voltage connection to be made to the phase interface of the electric machine after the power electronics module has been mounted to the gearbox housing.

[0017] According to a preferred embodiment, the DC voltage connection is arranged on the outside of the support element. This facilitates the establishment of an electrically conductive connection between a vehicle battery and the DC voltage connection during the installation of the transmission in the vehicle.

[0018] Preferably, the power electronics module has a cooling water supply connection and a cooling water discharge connection, which are arranged on the outside of the support element. Cooling water can be supplied to the power electronics module via the cooling water supply connection, in particular for cooling the power semiconductors of the inverter. The cooling water can be discharged from the power electronics module via the cooling water discharge connection.

[0019] Preferably, the power electronics module has a signal connector located on the outside of the carrier element. The signal connector is designed for signal transmission between an element of the power electronics module and a control unit external to the transmission.

[0020] By providing the various interfaces of the power electronics module to its carrier element, the power electronics module can be fully tested and pre-assembled before being attached to the gearbox housing.

[0021] According to a preferred embodiment, the support element includes a pressure equalization element by means of which the drying chamber is connected to the environment. This prevents the accumulation of moisture in the drying chamber caused by a pressure difference between the environment and the drying chamber. Alternatively, the support element can have a connection for a vent line by means of which the drying chamber is connected to the environment. The free end of the vent line can be located in a high-lying and water-protected area within the vehicle equipped with such a transmission. According to a further alternative, the drying chamber can be connected to the environment via at least one bore in the housing. The free end of this bore is preferably located in a high-lying and water-protected area of ​​the transmission. In this embodiment, the drying chamber is vented via this bore.

[0022] The transmission can be a component of a motor vehicle. In addition to the transmission, the motor vehicle also has an internal combustion engine, which may be torsionally connected to the transmission's input shaft via a torsional vibration damper. The transmission's output shaft is driven by a differential, either internal or external to the transmission, which in turn drives the vehicle's wheels. The motor vehicle with the transmission enables several drive modes. In electric mode, the vehicle is driven by the transmission's electric motor. In combustion engine mode, the vehicle is driven by the combustion engine. In hybrid mode, the vehicle is driven by both the combustion engine and the transmission's electric motor.

[0023] Exemplary embodiments of the invention are described in detail below with reference to the accompanying figures. These show: Fig. 1 to Fig. 3 each a schematic view of a gearbox for a motor vehicle; Fig. 4 a side view of a gearbox according to the invention with the power electronics module removed; Fig. 5 a sectional view of the gearbox according to the invention with mounted power electronics module; Fig. 6 a side view of the gearbox according to the invention with mounted power electronics module; Fig. 7 a side view of a variant of the gearbox according to the invention with a mounted power electronics module; and Fig. 8 a schematic view of a motor vehicle with the transmission according to the invention.

[0024] Fig. Figure 1 shows a schematic view of a transmission G for a motor vehicle. The transmission G comprises a housing GG, a gear set RS arranged within the housing GG, and a drive shaft GW1 and an output shaft GW2. The gear set RS serves to form several gears between the drive shaft GW1 and the output shaft GW2. The transmission G also includes an electric machine EM, whose rotor is operatively connected to the drive shaft GW1. The drive shaft GW1 is connected to a connecting shaft AN of the transmission G via a coupling K0. A drive interface GW1A is provided on the connecting shaft AN. An output interface GW2A is provided on the output shaft GW2. The drive interface GW1A and the output interface GW2A are arranged at opposite ends of the transmission G. The housing GG encloses not only the gear set RS but also the disconnect coupling K0 and the electric machine EM.

[0025] Fig. Figure 2 shows a schematic view of a gear G, which is essentially the same as the one in Fig. This corresponds to gearbox G as shown in Figure 1. The rotor of the electric machine EM is now operatively connected to the output shaft GW2. The connecting shaft AN and the disconnect coupling K0 are omitted, so that the drive interface GW1A is formed on the drive shaft GW1.

[0026] Fig. Figure 3 shows a schematic view of a gear G, which is essentially the same as the one described in Figure 3. Fig. This corresponds to the gearbox G shown in Figure 1. The rotor of the electric machine EM is now operatively connected to an element RSx of the gear set RS. The connecting shaft AN and the disconnect coupling K0 are omitted, so that the drive interface GW1A is formed on the drive shaft GW1.

[0027] The in Fig. 1 to Fig. The three gear units G shown are merely examples. For example, in designs according to Fig. 2 and Fig. 3. A disconnect coupling K0 and a connecting shaft AN are also provided. Each of the exemplary transmissions shown could have a torque converter arranged between the connecting shaft AN and the gear set RS.

[0028] Fig. Figure 4 shows a side view of a gearbox G. The construction of gearbox G can be exemplified by one of the following: Fig. 1 to Fig. The 3 illustrated versions correspond to this. The gearbox G in any case has an electric machine EM, which is arranged inside the housing GG, and therefore in Fig. 4 is not visible. The housing GG has an area GGE on an outer wall GGA, which is connected by means of a Fig. The area GGE, not shown, is lockable. The area GGE is bounded by a flange surface FF, which forms the mechanical interface between the housing GG and the power electronics module LE. A phase interface AC2 is located in the area GGE, which is assigned to the electrical machine EM located inside the housing GG.

[0029] The GGE area is located between the lower edge (UK) of the gearbox housing (GG) and half the overall height (GH2) of the gearbox housing (GG). In some sections, the GGE area extends above the lower third (GH3) of the overall height (GH) of the gearbox housing (GG). The phase interface (AC2) is partially located within a section of the GGE area that extends above the lower third (GH3) of the overall height (GH) of the gearbox housing (GG).

[0030] Fig. Figure 5 shows a sectional view of the gearbox G according to the invention, wherein the power electronics module LE is mounted on the gearbox housing GG. The in Fig. The specified section plane A passes through the wheelset RS, so that the wheelset RS is in Fig. 5 is partially visible. The power electronics module LE has a carrier element S with an inner surface SI and an outer surface SA, a DC voltage connection DC, an inverter INV, and an AC voltage connection AC connected to the phase interface AC2. The inverter INV is attached to the inner surface SI of the carrier element S. The area GGE of the housing GG and the inner surface SI of the carrier element S form a dry compartment TR for housing the inverter INV. In the section plane A, the area GGE of the housing GG separates the wheelset RS from the dry compartment TR.

[0031] The AC voltage connection is located within the dry chamber TR and is only partially visible in the given sectional view. A section of the AC voltage connection is located above the lowest third GH3 of the overall height GH of the gearbox housing GG. The DC voltage connection is located on the outer surface SA of the support element S and is situated within the lowest third GH3 of the overall height GH of the gearbox housing GG.

[0032] Fig. Figure 6 shows a side view of the transmission G according to the invention, in contrast to the illustration in Fig. 4. The power electronics module LE is mounted on the housing GG. It can be clearly seen that the power electronics module LE extends predominantly along the lower third GH3 of the overall height GH of the gearbox housing GG. The support element S has several openings, which are closed by means of covers C. If the covers C are removed, the AC voltage connection located on the inside SI of the support element S is accessible from the outside SA.

[0033] The power electronics module LE has a cooling water supply connection K1 and a cooling water discharge connection K2, which are located on the outer surface SA of the support element S. Cooling water can be supplied to a heat exchanger of the power electronics module LE via the cooling water supply connection K1. The heat exchanger is in thermal contact with power semiconductors of the inverter INV, allowing the power semiconductors to transfer heat energy to the heat exchanger. The supplied cooling water is heated in the heat exchanger and discharged from the power electronics module LE via the cooling water discharge connection K2. The cooled cooling water can then be supplied to a further heat exchanger, preferably located external to the gearbox.

[0034] The power electronics module LE has a signal connector I on the outer side SA of the carrier element S. The signal connector I is for signal transmission between an element of the power electronics module LE, in particular a controller of the inverter INV, and a component in Fig. The transmission is equipped with an external control unit (ECU) of 6 (not shown). The power electronics module (LE) also features a pressure equalization element (D) by means of which the dry chamber (TR) is connected to the environment. This prevents the accumulation of moisture in the dry chamber (TR) caused by a pressure difference between the environment and the dry chamber (TR).

[0035] Fig. Figure 7 shows a side view of a variant of the transmission G according to the invention, which is essentially the same as the one described in Figure 7. Fig. The gearbox G shown in Figure 6 corresponds to this. Instead of the pressure equalization element D, the support element S now has a connection for a vent line DS. The dry chamber TR is connected to the environment via the vent line DS. The free end of the vent line DS can be located in a high-lying and water-protected area within the vehicle equipped with such a gearbox G.

[0036] Fig. Figure 8 shows a schematic view of a motor vehicle with the transmission G according to the invention. The transmission G is connected to an internal combustion engine VM via the drive interface GW1A. The transmission G is connected to a differential (not shown) via the output interface GW2A, through which the power applied to the output shaft GW2 is distributed to the drive wheels DW of the motor vehicle.

[0037] The vehicle has an electronic control unit (ECU) designed to control the vehicle's hybrid drive functions. The ECU is connected to the internal combustion engine (VM) and, via signal connector I, to the power electronics module (LE) of the transmission (G) for signal transmission. The ECU may also be connected to other vehicle components, such as a battery. Reference sign G gearbox GW1 drive shaft GW2 output shaft GW1A drive interface GW2A output interface RS wheelset RSx wheel set element EM Electrical Machine AC2 phase interface of the electrical machine GG housing GGE area of ​​the housing GGA outer wall of the housing FF flange surface UK bottom edge of the case GH Housing height GH2 Half the case height GH3 third of the case height LE Power Electronics Module S support element SI inside of the support element SA Outer side of the support element DC power connection AC power connection INV inverter A cutting plane TR Drying Room C lid K1 Cooling water supply connection K2 cooling water drain connection I Signal connector ECU control unit The pressure equalization element DS vent line VM internal combustion engine K0 disconnect coupling ON connection shaft DW drive wheel

Claims

[1] Transmission (G) for a motor vehicle, wherein the transmission (G) comprises a housing (GG), a gear set (RS) arranged within the housing (GG) for forming multiple gears between a drive shaft (GW1) and an output shaft (GW2) of the transmission (G), an electric machine (EM) operatively connected to the drive shaft (GW1), the output shaft (GW2) or an element (RSx) of the gear set (RS), and a power electronics module (LE), - wherein the power electronics module (LE) comprises a carrier element (S) with an inside (SI) and an outside (SA), a DC voltage connection (DC), an inverter (INV) and an AC voltage connection (AC) connected to a phase interface (AC2) of the electric machine (EM), - wherein the housing (GG) has an area (GGE) on an outer wall (GGA) for receiving the power electronics module (LE), which can be closed by the carrier element (S) of the power electronics module (LE), - wherein the area (GGE) of the housing (GG) and the inside (SI) of the support element (S) form a dry space (TR) for receiving the inverter (INV) which is attached to the support element (S), and - wherein the area (GGE) of the housing (GG) separates at least partially the wheelset (RS) from the drying room (TR), characterized by, that the area (GGE) for receiving the power electronics module (LE) is located between a lower edge (UK) of the gearbox housing (GG) and half the height (GH2) of the gearbox housing (GG), wherein the area (GGE) extends at least partially above the lower third (GH3) of the height (GH) of the gearbox housing (GG), wherein at least a part of the AC voltage connection (AC) is arranged in that section of the power electronics module (LE) which extends above the lower third (GH3) of the height (GH) of the gearbox housing (GG). [2] Gearbox (G) according to claim 1, characterized by , that the power electronics module (LE) is located laterally on the gearbox housing (GG). [3] Gearbox (G) according to claim 1 or claim 2, characterized by, that the gearbox (G) has a drive interface (GW1A) and an output interface (GW2A), wherein the drive interface (GW1A) and the output interface (GW2A) are arranged at opposite ends of the gearbox (G), wherein the power electronics module (LE) is arranged between the drive interface (GW1A) and the output interface (GW2A) and extends at least section by section to above the lower third (GH3) of the overall height (GH) of the gearbox housing (GG). [4] Gearbox (G) according to claim 1, characterized by , that the power electronics module (LE) has a lower overall height in certain sections than one-third (GH3) of the overall height (GH) of the gearbox housing (GG). [5] Gearbox (G) according to claim 4, characterized by, that the DC voltage connection (DC) is located in that section of the power electronics module (LE) which has a lower height (LEH) than one third (GH3) of the height (GH) of the gearbox housing (GG). [6] Gearbox (G) according to any one of claims 1 to 5, characterized by , that the power electronics module (LE) extends predominantly along the lower third (GH3) of the overall height (GH) of the gearbox housing (GG). [7] Gearbox (G) according to any of the preceding claims, characterized by that the support element (S) has openings which can be closed by means of one or more covers (C). [8] Gearbox (G) according to claim 7, characterized by , that the alternating current connection (AC) is located on the inside (SI) of the support element (S), and is accessible through the openings from an outside (SA) of the support element (S). [9] Gearbox (G) according to any of the preceding claims, characterized by , that the DC voltage connection is located on the outside (SA) of the support element (S). [10] Gearbox (G) according to any of the preceding claims, characterized by , that the power electronics module (LE) has a cooling water supply port (K1) and a cooling water discharge port (K2) which are located on the outside (SA) of the carrier element (S). [11] Gearbox (G) according to any of the preceding claims, characterized by , that the power electronics module (LE) has a signal connector (I) on the outside (SA) of the carrier element (S) which is set up for signal transmission between an element of the power electronics module (LE) and a transmission-external control unit (ECU). [12] Gearbox (G) according to any of the preceding claims, characterized by , that the support element (S) has a pressure equalization element (D) by means of which the dry room (TR) is connected to the environment. [13] Gearbox (G) according to any one of claims 1 to 12, characterized by that the support element (S) has a connection for a vent line (DS). [14] Gearbox (G) according to any one of claims 1 to 12, characterized by that the dry room (TR) is connected to the environment via at least one bore in the housing (GG). [15] Motor vehicle with a transmission (G) according to at least one of claims 1 to 14.

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