Hybrid powertrain

Abstract

Hybrid drive train (1) with an internal combustion engine (10) and at least one electric machine (9), both of which engage in a transmission (2) that comprises at least one transmission input shaft (5) and at least one transmission output shaft (8), wherein the transmission (2) is arranged in front of or behind the internal combustion engine (10) in the vehicle's longitudinal direction and parallel to the internal combustion engine (10), characterized in that a transmission input shaft (5) is arranged concentrically to a differential (4), designed as a hollow shaft and radially encloses an axle side shaft (20) that is connected in a rotationally fixed manner to an output of the differential (4); characterized in that the transmission output shaft (8) is installed vertically in a plane (L2) above the transmission input shaft (5) with the axle side shaft (20) and the electric machine (9) has a installation space which extends along the vehicle transverse axis (y-axis) above the plane (L2) and up to the entire length (Ly) of the transmission (2).

Description

[0001] The invention relates to a hybrid drive train with an internal combustion engine and an electric machine, both of which engage in a transmission, wherein the transmission is arranged in front of or behind the internal combustion engine in the vehicle longitudinal direction and parallel to the internal combustion engine. State of the art

[0002] Hybrid drives with two or more different drive sources can contribute to reducing fuel consumption and pollutant emissions in vehicle traffic. To achieve the most effective operation of the hybrid drive, drive strategies are used that flexibly utilize an electric drive depending on the situation, for example, for starting, as the sole drive source in short urban traffic or in stop-and-go operation, as an additional drive source for increased power requirements in boost mode, as a starter generator for quickly starting the combustion engine, as a generator for power generation, or for energy recovery in recuperation mode. The combustion engine, on the other hand, should be operated at least predominantly at operating points with favorable fuel consumption, torque, and speed while maintaining high efficiency.

[0003] In hybrid vehicles, transmissions are known which, in addition to a gear set, also have one or more electric motors. The transmission is usually designed with multiple gears, i.e. several different gear ratios can be switched as gears between an input shaft and an output shaft by actuating corresponding switching elements, this often happening automatically. Depending on the arrangement of the switching elements, these can be clutches or brakes. The transmission is used to suitably implement the tractive power supplied by a drive motor of the motor vehicle with regard to various criteria. The gears of the transmission are usually used in conjunction with the at least one electric motor to represent purely electric driving. The at least one electric motor can also often be integrated into the transmission in different ways to represent different operating modes.

[0004] Such a transmission is known, for example, from DE 10 2021 200 255 A1. The hybrid transmission is arranged behind an internal combustion engine in the direction of travel. The torque of the internal combustion engine is transmitted to a first transmission shaft via a belt or chain, i.e., a connection. From there, torque can be transferred to a second transmission shaft, which is operatively connected to an electric motor via a planetary gear. A differential transfers the resulting torque to the driven wheels of the vehicle. The electric motor is installed behind and parallel to the internal combustion engine in the direction of travel.

[0005] The differential sits on its own axle, which runs along the vehicle's z-axis, i.e. vertically at the lowest point compared to the other axes of the other shafts.

[0006] The installation space around the differential and the axle shafts and / or drive shafts extending from it is unused. This worsens the situation, especially for the electric motor and the inverter. Furthermore, the lubrication situation is poor, as the transmission shafts must be positioned above the differential.

[0007] DE 10 2020 104 791 A1 describes a transmission assembly comprising a first transmission input shaft and a second transmission input shaft. The first transmission input shaft and the second transmission input shaft are coupled to a first planetary gear in a torque-conducting manner. Furthermore, a transmission output shaft of the transmission assembly is coupled to a second planetary gear in a torque-conducting manner. A first spur gear is arranged in the power flow between the first planetary gear and the second planetary gear. The structural arrangement of the shafts relative to one another is not further described.

[0008] The object of the invention is to provide a hybrid transmission arrangement in which the lubrication situation is improved and the available installation space for the electric machine and the inverter is larger. Description of the invention

[0009] The object is achieved with a hybrid drive train with an internal combustion engine and an electric machine, both of which engage in a transmission that comprises at least one transmission input shaft and at least one transmission output shaft, wherein the transmission is arranged in front of or behind the internal combustion engine in the vehicle longitudinal direction and parallel to the internal combustion engine, wherein a transmission input shaft is arranged concentrically to a differential, designed as a hollow shaft and radially encloses an axle side shaft that is connected in a rotationally fixed manner to an output of the differential.

[0010] It is advantageous that a transmission input shaft with axle side shaft and concentrically arranged differential is installed in a lowest level L1 in the vertical direction, the z-axis of the transmission.

[0011] It is advantageous that the gearbox output shaft is installed vertically in a plane L2 above the gearbox input shaft with axle side shaft.

[0012] Advantageously, the electric machine has a rotor shaft which is located in the plane L3 vertically above the plane L2.

[0013] The vertically stacked shafts and shaft combinations allow for a very compact design, while still providing space for the electrical motors. The lubrication situation is optimized.

[0014] The electric motor has a mounting space that extends along the vehicle's transverse axis (y-axis) above the L2 plane and up to the entire length of the transmission. The mounting space is as long as the transmission, allowing for the installation of an electric motor of this length.

[0015] The invention allows the transmission shafts to be installed deeper and improves lubrication. Furthermore, the available package for the electric motor and inverter is larger. Description of the characters Fig. 1a shows a drive train, with the combustion engine located in front of the transmission, seen in the direction of travel, Fig. 1b shows a drive train, with the combustion engine located behind the transmission, seen in the direction of travel, Fig. 2a shows an unfolded transmission section related to the vehicle zy-plane, Fig. Figure 2b shows an isometric view of the hybrid powertrain.

[0016] The Fig. 1a and Fig. 1b shows views from above of a drive train 1, whereby it is not a sectional view of one plane, but the individual shafts lie in different sectional planes of the z-axis and are unfolded.

[0017] The two arrangements differ only in that in one case a transmission 2 is located before and in the other case after an internal combustion engine 10. The transmission 2 is arranged transversely to the direction of travel, in the y-direction.

[0018] The combustion engine is connected to a transmission input shaft 5 via a chain drive 3. This, in turn, is designed as a hollow shaft and arranged concentrically with a differential 4. An axle side shaft 20, which is connected to a drive shaft 22 (not shown in detail), is designed as a solid shaft and arranged within the transmission input shaft 5 and connected to the differential 4.

[0019] The transmission 2 comprises a transmission output shaft 8, which drives the differential 4. The torque is transmitted via the differential to the right-hand drive shaft 22 in the direction of travel (negative x-axis) and via the axle side shaft 20 to the left-hand drive shaft 22 in the direction of travel (negative x-axis). An electric machine 9 also drives into the transmission 2.

[0020] The spatial arrangement of the gearbox is in the Fig. 2a and Fig. 2b. The Fig.Figure 2a shows an unfolded transmission section relative to the yz-plane of the vehicle. In the vehicle, the shaft located lowest in the z-direction is located on plane L1: the axle side shaft 20 with the transmission input shaft 5, which is designed as a hollow shaft.

[0021] Since no additional separate axle is provided for the differential 4, but rather the axle side shaft 20 is used as the inner shaft of the hollow shaft of the transmission input shaft 5, the differential 4 is also arranged at a low point of the transmission 2. The transmission output shaft 8 is arranged above level L1. On this level L2 there is a clutch pack 12 as well as gear wheels of different gear stages and switching devices of the transmission output shaft 8. Level L3 marks the rotor axis 13 of the electric machine 9. The electric machine 9, together with an inverter 11, can use the entire installation space available along the y-axis above the transmission 2 in this installation position arranged above the transmission shafts.

Claims

[1] Hybrid drive train (1) with an internal combustion engine (10) and at least one electric machine (9), both of which engage in a transmission (2) comprising at least one transmission input shaft (5) and at least one transmission output shaft (8), wherein the transmission (2) is arranged in front of or behind the internal combustion engine (10) in the vehicle longitudinal direction and parallel to the internal combustion engine (10), characterized by that a transmission input shaft (5) is arranged concentrically to a differential (4), designed as a hollow shaft and radially encloses an axle side shaft (20) which is connected in a rotationally fixed manner to an output of the differential (4); characterized by that the transmission output shaft (8) is installed vertically in a plane (L2) above the transmission input shaft (5) with the axle side shaft (20) and the electric machine (9) has a space that extends along the vehicle transverse axis (y-axis) above the plane (L2) and up to the entire length (Ly) of the transmission (2). [2] Hybrid powertrain according to claim 1, characterized by that a transmission input shaft (5) with the axle side shaft (20) and concentrically arranged differential (4) is arranged in a lowest plane (L1) in the vertical direction (z-axis) of the transmission (2). [3] Hybrid drive train according to one of the preceding claims, characterized by that the electrical machine (9) has a rotor shaft which lies in a plane (L3) above the plane (L2).

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