Multi-Epicyclic Friction Transmission With Rolling Cones for Higher Torque
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Solution Overview
Problem
Current transmission systems for electric vehicles, particularly epicyclic gearing with friction drives, face inefficiencies and challenges in duplicating gear configurations, limiting their torque capacity and range anxiety issues due to low power transmission efficiency.
Innovation Solution
An infinitely variable multi-epicyclic friction transmission system utilizing a stack of epicyclic friction gears in series, with a cylindrical drum, axial flux motor, twin planetary cone assemblies, and pressuriser rings to enhance torque capacity through rolling friction, allowing for efficient power transmission to road wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If friction drives are used in epicyclic gearing, then torque capacity is increased, but power transmission efficiency deteriorates
Solution Approach 1:
The transmission system is divided into multiple independent epicyclic friction gear stacks connected in series. Each stack contains planet gears, sun gears, and ring gears that can be independently designed and optimized. This segmentation allows the system to achieve high torque capacity through cumulative effect while maintaining manageable efficiency at each stage.
Solution Approach 2:
Multiple epicyclic gear stacks are nested within a common housing structure, with each stack containing concentric arrangements of sun gears, planet gears, and ring gears. The nested configuration maximizes space utilization and allows torque to be accumulated through the series connection of multiple stacks, thereby increasing overall torque capacity while controlling efficiency losses.
2Force
If multiple epicyclic friction gear stacks are used in series, then torque capacity is significantly increased, but device complexity increases
Solution Approach 1:
The complex transmission system is segmented into identical or similar modular epicyclic friction gear stacks. Each module contains the complete set of sun gear, planet gears, and ring gear components. This modular segmentation allows the complex torque multiplication function to be achieved through repetition of standardized units, making the overall system complexity manageable through modularity.
Solution Approach 2:
Multiple epicyclic gear stacks are combined in series within a common housing, sharing common input and output shafts. The merging of multiple simple friction drive stages creates the complex torque multiplication effect needed for high-performance electric vehicle applications, while the unified housing structure helps manage overall system complexity.
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 system significantly increases torque output, analogous to a multi-plate clutch, enabling efficient power transmission to road wheels, addressing range anxiety and inefficiency issues in existing systems.
Implementation Method 1
an infinitely variable multi-epicyclic friction transmission system which relies solely on rolling friction
Implementation Method 2
the vee-rings are configured to be compressed together by a pressuriser ring at a distal end of the cylindrical drum, thus forcing the spherical planets radially outwards to abut the torque tubes
Implementation Method 3
an axial flux motor comprising a stator which is fixedly located in one of the casings side plates
Data Source
AI summary
Infinitely variable multi-epicyclic friction transmission system including a main shaft, ball race discs, a splined tube, and twin planetary cone assemblies attached to a planetary carrier and disposed circumferentially around the splined tube. Each twin planetary cone assembly comprises a torque tube and a planetary cone-hemisphere structure comprising a planetary cone integral with hemisphere at its apex, wherein the planetary cone-hemisphere structure rolls inside the torque tube via the hemisphere, and wherein a slant height of the twin planetary cone assemblies is parallel to the main shaft. System also includes a series of spherical planets, a reaction ring disposed around the twin planetary cone assemblies configured to slide along the planetary cone assemblies to vary a gear ratio, and ball gear retaining rings. Each of the ball gear retaining rings is mounted on one of a plurality of ball gears which are mounted on the ball race discs.