Hybrid Drive Train Axial Electric Machine Layout
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Solution Overview
Problem
Existing drive trains for hybrid motor vehicles require significant installation space due to the radial arrangement of electric machines around planetary gearsets, which limits compact design possibilities.
Innovation Solution
The drive train incorporates a shiftable planetary gearset allowing the electric machine to be coupled to the engine shaft via a speed-transforming spur wheel gear, positioned axially parallel to the engine shaft, reducing the electric machine's radial dimensions and enabling a smaller installation space by using an intermediate shaft to introduce torque into the planetary gearset, thus reducing the overall drive train size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the electric machine is arranged radially around the planetary gearset, then the torque transmission is direct, but the installation space requirement increases
Solution Approach 1:
The electric machine is repositioned from a radial arrangement around the planetary gearset to an axial arrangement adjacent to it. This dimensional change allows the electric machine to be connected via an intermediate shaft and speed-transforming gear, reducing the radial extent and installation space while maintaining torque transmission capability
Solution Approach 2:
An intermediate shaft is introduced as a mediator between the electric machine and the planetary gearset. This intermediate shaft, combined with a speed-transforming gear, enables torque transmission from the electric machine to the planetary gearset without requiring direct radial contact, thereby reducing installation space requirements
2Speed
If the electric machine acts directly on the planetary gearset, then the speed reduction is sufficient, but the centrifugal forces and loads on the planetary gearset increase
Solution Approach 1:
A speed-transforming gear is introduced as an intermediary between the electric machine and the planetary gearset. This additional speed transformation stage reduces the speed of the electric machine before it acts on the planetary gearset, thereby reducing centrifugal forces and loads on the planetary gearset components
Solution Approach 2:
The system modifies the speed parameter of the electric machine output by introducing an additional speed-transforming gear with a specific transmission ratio. This parameter change reduces the rotational speed transmitted to the planetary gearset, consequently reducing centrifugal forces and mechanical loads
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for a compact drive train design with reduced installation space requirements, enabling lower production costs and reduced centrifugal loads on the planetary gearset, while maintaining high torque delivery for starting the internal combustion engine and powering auxiliary units.
Implementation Method 1
an electric machine (30) for supplying a torque to drive the hybrid motor vehicle, wherein the electric machine (30) can be coupled to the engine shaft (18), in particular in order to start the internal combustion engine (12), via a shiftable planetary gearset (38) for supplying at least two different transmission ratios
Implementation Method 2
the electric machine (30) can be coupled, via a speed-transforming gear, in particular a spur wheel gear (48), having a transmission ratio differing from 1.0, to an intermediate shaft (46)
Data Source
AI summary
The invention relates to a drive train (10) for a hybrid vehicle comprising an internal combustion engine (12) having a motor shaft (18) for providing a torque for driving the hybrid vehicle, and comprising an electric machine (30) for providing a torque for driving the hybrid vehicle, wherein the electric machine (30), in particular for starting of the internal combustion engine (12), can be coupled to the motor shaft (18) by means of a selectively engageable planetary gear unit (38) for providing at least two different transmission ratios, wherein the electric machine (30) can be coupled by means of a transmission gearing (48), in particular a sun gear system having a transmission ratio different from 1.0, having an intermediate shaft (46) for introducing the torque into the planetary gear unit (38).