Compact Planetary Gear Transmission for Electric Vehicle Wheel Integration
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Solution Overview
Problem
Current electric vehicle transmission apparatuses have complex, large, and axially long structures, making them difficult to install in vehicle wheels, especially when performing high torque low speed rotation, low torque high speed rotation, braking, and opening operations.
Innovation Solution
A transmission apparatus with a compound planetary gear set that includes a sun gear, planetary gears, ring gears, a cage, and a brake member, allowing for multi-stage variable-speed rotation, stopping, and opening operations with a simple and compact structure, reducing size and axial extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an existing transmission apparatus is used to achieve high torque low speed rotation and low torque high speed rotation, then the speed-torque characteristics are improved, but the structure becomes complicated and the size increases making it difficult to install in vehicle wheels
Solution Approach 1:
The patent combines multiple transmission functions (high torque low speed rotation, low torque high speed rotation, braking, and opening operations) into a single integrated transmission apparatus with a compact planetary gear set, eliminating the need for separate transmission systems and reducing overall structural complexity while maintaining all required functions
Solution Approach 2:
The transmission apparatus is designed to perform multiple functions simultaneously - it provides both high torque low speed rotation and low torque high speed rotation capabilities, along with braking and opening operations, making it a universal solution that replaces multiple separate systems and simplifies the overall vehicle wheel assembly
2Speed
If an existing transmission apparatus is used to achieve multi-stage variable-speed rotation, then the speed control is improved, but the axial length increases making it difficult to install in vehicle wheels
Solution Approach 1:
The patent employs a nested planetary gear configuration where planetary gears are arranged concentrically around a sun gear, with ring gears enclosing the planetary gears. This nested arrangement achieves multi-stage variable-speed rotation while minimizing axial length, as the gear stages are stacked radially rather than extending axially
Solution Approach 2:
The transmission apparatus transitions from axial extension to radial arrangement by nesting gear components in concentric circles. The multi-stage speed variation is achieved through radial layering of planetary gears and ring gears rather than axial stacking, thereby reducing the axial length to fit within vehicle wheel constraints
3Use of energy by moving object
If a mechanical transmission apparatus is used with the electric motor, then the energy efficiency is improved, but the structure becomes complicated and the size increases
Solution Approach 1:
The patent integrates the mechanical transmission apparatus directly with the electric motor in a compact configuration, merging the motor housing and transmission housing into a unified structure. This integration maintains the energy efficiency benefits of mechanical transmission while minimizing the overall volume occupied by the combined motor-transmission system
Solution Approach 2:
The planetary gear set is nested within a compact housing that is integrated with the motor structure. The sun gear, planetary gears, and ring gears are arranged in concentric circles that fit within the motor's radial space, eliminating the need for separate transmission housing and reducing the total volume of the motor-transmission assembly
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
Enables efficient energy use, improved space utilization, and effective performance in electric vehicles by simplifying the structure and enhancing the ability to perform various operational requirements within the vehicle wheel.
Implementation Method 1
a brake member, wherein the brake member acts on the second ring gear and on the cage so as to control rotation of the second ring gear and rotation of the cage
Data Source
AI summary
Disclosed is a transmission apparatus comprising: a sun gear connected to the input terminal; a plurality of first planetary gears engaging with an outer surface of the sun gear; a second planetary gear which forms a concentric circle with each first planetary gear, and which is integrally formed with the first planetary gears; a first ring gear engaging with outer surfaces of the first planetary gears and connected to the output terminal; a second ring gear engaging with an outer surface of the second planetary gear; a cage for supporting rotary shafts of the first and second planetary gears such that the first and second planetary gears can revolve about the sun gear; and a brake member.