In-Wheel Drive Layout With Planetary Reduction for Lower Power Loss
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Solution Overview
Problem
Existing motor vehicle drive axle systems have a long transmission chain, leading to high power loss and lower efficiency, which affects driving distance, and the conventional axle layout compromises passenger capacity and vehicle design, especially in new energy buses.
Innovation Solution
An in-wheel drive system incorporating a hub, driving motor, rotor support, and planetary gear reducers, which eliminates the need for a conventional transmission half axle and differential by directly driving the wheel, reducing the transmission chain length and enhancing vehicle layout flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional drive axle system with central driving motor, clutch, transmission, and differential is used, then the vehicle can achieve reliable power transmission, but the transmission chain becomes long, power loss increases, and system efficiency decreases
Solution Approach 1:
The patent extracts and removes intermediate transmission components (clutch, transmission gears, differential, drive shafts) from the conventional power transmission path. The driving motor is directly integrated into the wheel hub assembly, eliminating the need for these intermediate components and thereby shortening the transmission chain while reducing power loss.
Solution Approach 2:
The patent merges the driving motor, planetary gear reducer, and wheel hub into a single integrated in-wheel drive assembly. This consolidation eliminates multiple separate components and their connecting transmission elements, directly reducing transmission chain length and associated energy losses while maintaining reliable power transmission.
2Adaptability or versatility
If a conventional axle system with differential and multiple transmission parts is used, then power transmission is reliable, but the vehicle layout design is constrained and passenger capacity is reduced
Solution Approach 1:
The patent removes the differential and other intermediate transmission parts from the conventional axle system. By integrating the driving motor directly into the wheel hub, the system eliminates components that traditionally constrained vehicle layout design, thereby increasing layout flexibility and allowing for optimized passenger capacity.
Solution Approach 2:
The patent transitions from a centralized transmission system to a distributed in-wheel drive architecture. This dimensional change in system architecture eliminates the need for long transmission shafts and differentials, freeing up space in the vehicle layout and enabling more flexible arrangement of passenger compartments and other vehicle components.
3Productivity
If a conventional transmission system with multiple gears and shafts is used, then the system can handle varying load conditions, but the overall system efficiency decreases
Solution Approach 1:
The patent extracts and eliminates multiple transmission components including clutch, transmission gears, and drive shafts from the power transmission path. This reduction in component quantity directly improves system efficiency by minimizing energy losses at each transmission interface while the integrated in-wheel drive design maintains the ability to handle varying load conditions.
Solution Approach 2:
The patent combines the driving motor, planetary gear reducer, and wheel hub into a single integrated unit. This merging eliminates numerous separate transmission components and their associated connection points, thereby reducing the overall number of components and improving system efficiency through reduced energy loss.
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 in-wheel drive system shortens the transmission chain, improves efficiency, and allows for a more compact vehicle design, enabling easier torque vector control and increased passenger space in new energy vehicles.
Implementation Method 1
The planetary gears mesh with the sun gear shafts on the outer radial sides of the sun gear shafts
Implementation Method 2
The ring gear meshes with the planetary gears on the outer radial sides of the planetary gears
Implementation Method 3
The driving motor includes a stator and a rotor that rotates relative to the stator
Data Source
AI summary
An in-wheel drive system includes a hub, a driving motor, a rotor support fixed to a rotor of the driving motor on the inner radial side of the rotor, and planetary gear reducers. The planetary gear reducer comprises a sun gear shaft, a planetary gear, a ring gear, and a planetary gear carrier, wherein the sun gear shaft is fixed to the rotor support on the outer radial side of the hub, and the planetary gear carrier is fixed to the hub. A driving force/torque is transmitted to the hub via the rotor, the rotor support, the sun gear shaft, the planetary gear, and the planetary gear carrier. The in-wheel drive system removes the need for a conventional transmission half axle, differential, and other transmission parts, shortens the transmission chain, is conducive to the vehicle layout design, and can easily implement torque vector control.