Compact Planetary Differential for Drive Module Packaging
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Solution Overview
Problem
Existing drive modules with differential gearsets are challenging to package into vehicles due to their overall length, limiting their integration in certain vehicle designs.
Innovation Solution
A compact drive module incorporating a planetary differential assembly with compound gears and different pitch diameters for the output sun gears, allowing for a 50-50 torque split between axle shafts, which are coupled to the first and second output sun gears for rotation, enabling efficient packaging and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional differential gearset with bevel gears is used, then propulsion and torque vectoring capabilities are provided, but the overall length in the lateral direction increases making packaging difficult
Solution Approach 1:
The patent transitions from a traditional lateral differential arrangement to a longitudinal planetary differential arrangement. The planetary differential assembly is positioned along the longitudinal axis of the drive module, with the input pinion receiving power from the motor along the longitudinal direction and the output sun gears connected to axle shafts extending longitudinally. This dimensional reorientation significantly reduces the lateral footprint while maintaining differential functionality.
Solution Approach 2:
The planetary differential assembly employs a nested configuration where planet gears are positioned between the input ring gear and output sun gears, creating a compact layered structure. The compound planet gears have first and second gear portions with different pitch diameters, allowing one gear portion to mesh with the input ring gear while the other meshes with the output sun gear, effectively nesting multiple gear functions within a confined radial space.
2Length of moving object
If compound planet gears with different pitch diameters are used, then compact packaging is achieved, but the gear design complexity increases
Solution Approach 1:
The planet gears are segmented into compound gears with distinct first and second gear portions, each having different pitch diameters and serving different meshing functions. The first gear portion meshes with the input ring gear while the second gear portion meshes with the output sun gear. This segmentation allows each gear portion to be optimized for its specific function while maintaining a unified planet carrier structure that holds all planet gears.
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
The compact design facilitates easier integration into vehicles while maintaining propulsion and torque vectoring capabilities, addressing the packaging challenges of traditional drive modules.
Implementation Method 1
The first planet gears are meshingly engaged with the first output sun gear... Each of the second planet gears is meshingly engaged with the second output sun gear
Data Source
AI summary
A drive module that includes an electric motor, an input pinion driven by the electric motor, a transmission driven by the input pinion, a planetary differential assembly and first and second axle shafts. The transmission has a first transmission output member. The planetary differential assembly has an input ring gear, a first output sun gear and a second output sun gear. The first and second output sun gears have different pitch diameters, different modules and a common quantity of sun gear teeth. The planetary differential assembly is configured to provide a 50-50 torque split between the first and second output sun gears. The first axle shaft is coupled to the first output sun gear for rotation therewith. The second axle shaft is coupled to the second output sun gear for rotation therewith.