Dual-Tire Electric Wheel Assembly With Nested Hub Reduction
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Solution Overview
Problem
Conventional commercial vehicles with centralized drive systems face limitations in power density, reliability, and dynamic performance due to long transmission chains and bulky components, which restrict their development for long lengths and heavy loads, and existing distributed electric drive systems struggle to meet torque requirements with large reduction mechanisms, making them unsuitable for parallelly mounted dual-tire wheels and non-independent suspensions.
Innovation Solution
An electric wheel assembly for parallelly mounted dual-tire wheels, featuring an internal-rotor hub motor, planetary gear reducer, and drum brake system, optimized for compactness and lightweight design, allowing integration with traditional leaf spring suspensions and reducing unsprung weight, with integrated cooling and lubrication for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a planetary gear reducer with large speed ratio is adopted to meet torque requirement, then torque output is improved, but device complexity and space occupation increase
Solution Approach 1:
The patent integrates the planetary gear reducer directly within the hub motor structure, nesting the reduction mechanism inside the motor housing. The sun gear is coaxial with the motor shaft, planetary gears are arranged around it, and the ring gear is integrated with the motor housing, creating a compact nested configuration that reduces overall device complexity while maintaining large torque output capability
Solution Approach 2:
The patent merges the hub motor and planetary gear reducer into a single integrated electric wheel assembly. The motor housing serves dual functions as both motor enclosure and ring gear carrier, the sun gear is directly coupled to the motor shaft, and the planet carrier is integrated with the hub structure, combining multiple components into unified assemblies that reduce complexity
2Force
If a planetary gear reducer with large speed ratio is adopted to meet torque requirement, then torque output is improved, but the electric wheel becomes unsuitable for parallelly mounted dual-tire wheels
Solution Approach 1:
The planetary gear reducer is nested within the hub motor structure, with the sun gear inside the stator, planetary gears arranged in the annular space between sun gear and ring gear, and the planet carrier integrated with the hub. This nested arrangement minimizes the radial and axial dimensions of the electric wheel assembly, making it suitable for parallelly mounted dual-tire wheels while maintaining large torque output through the high speed ratio
3Power
If a two-stage reducer and disc brake are adopted in low-floor electric axle, then power transmission is improved, but axial space occupation increases
Solution Approach 1:
The patent merges the single-stage planetary gear reducer with the drum brake system into an integrated assembly. The ring gear serves as the brake drum, brake shoes are mounted on the motor housing and press against the ring gear, and the brake actuator is integrated with the motor mounting structure. This merging eliminates the need for separate disc brake components and reduces axial space while maintaining effective power transmission and braking capability
4Force
If hub motor with reduction drive configuration is adopted to meet torque requirement, then torque output is improved, but unsprung weight increases
Solution Approach 1:
The patent employs high-strength materials and optimized structural parameters to reduce the weight of the planetary gear reducer and motor housing. The gear teeth are designed with optimized module and pressure angle, the planet carrier uses ribbed reinforcement instead of solid structure, and the motor housing is designed with thin-walled reinforced sections, all achieving weight reduction while maintaining the large torque output capability required for heavy-duty applications
Data Source
AI summary
Disclosed are an electric wheel assembly applicable for a parallelly mounted dual-tire wheel, an axle, and a vehicle. The electric wheel assembly includes a wheel and support axle assembly, an internal-rotor hub motor, a planetary gear reducer and a brake system. A planetary carrier is connected to a hub. The hub is connected to a spoke and a rim. The wheel support axle passes through a rotor sleeve and is provided with a hub bearing to support the hub and a whole wheel. A sun gear disposed at an end of the rotor sleeve of the internal-rotor hub motor is a power input of the planetary gear speed reducer, and the planetary carrier is a power output. A planetary gear of the planetary gear reducer is a tower-shaped gear and realizes a relatively high transmission ratio under a condition that an axial length is relatively small.