Hub Motor Assembly With Planetary Reduction for Low-Speed Torque
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Solution Overview
Problem
Existing hub motors, either inner rotor or outer rotor, face space inefficiencies or low torque issues, with inner rotors occupying excessive space and outer rotors having insufficient torque at low speeds.
Innovation Solution
A hub motor assembly incorporating an outer rotor motor with a planetary deceleration mechanism, where the outer rotor motor drives a planetary gear system that meshes with inner and outer ring gears to transmit power efficiently, reducing overall size while maintaining high torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If an inner rotor hub motor is used, then the output torque is large and climbing performance is good, but the lateral length increases which is not conducive to effective use of overall space
Solution Approach 1:
The planetary deceleration mechanism is nested inside the hub motor assembly, with the planetary carrier, planetary gears, and ring gears arranged concentrically around the rotor. This nesting allows the deceleration mechanism to occupy the radial space efficiently without significantly increasing the lateral length of the motor assembly.
Solution Approach 2:
The patent transitions from a traditional lateral deceleration mechanism to a radial deceleration mechanism by arranging the planetary gears and ring gears in a radial configuration around the rotor. This dimensional change allows the deceleration function to be integrated within the radial space of the hub motor, reducing the lateral length while maintaining torque multiplication capability.
2Power
If an outer rotor hub motor is used, then the output torque and output power are higher, but the output torque at low speed is small and the motor volume increases which takes up a lot of space
Solution Approach 1:
The patent changes the speed parameter through the planetary deceleration mechanism, reducing the rotational speed of the outer rotor while multiplying the output torque. This parameter transformation allows the motor to deliver high torque at low speeds without requiring a larger motor volume, as the deceleration mechanism efficiently converts the high-speed, low-torque rotor output into low-speed, high-torque wheel output.
Solution Approach 2:
The planetary deceleration mechanism acts as an intermediary between the outer rotor and the wheel, mediating the power transmission by reducing speed and increasing torque. This intermediary mechanism allows the outer rotor to maintain its compact design while still achieving high torque output at low speeds through the gear reduction.
3Volume of moving object
If the planetary deceleration mechanism is integrated into the hub motor, then the overall size is reduced and space utilization is optimized, but the device complexity increases
Solution Approach 1:
The patent merges the deceleration mechanism with the hub motor by integrating the planetary carrier, planetary gears, and ring gears directly into the motor assembly. The planetary carrier is connected to the rotor, the planetary gears mesh with both the inner and outer ring gears, and the entire deceleration system is housed within the hub structure. This merging reduces the overall size by eliminating separate deceleration components while the modular design of the planetary mechanism helps manage the structural 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 assembly achieves high torque output at low speeds with a compact design, suitable for new energy vehicles, optimizing space utilization and performance.
Implementation Method 1
The planetary gear is internally meshed with the outer ring gear and externally meshed with the inner ring gear
Implementation Method 2
The outer rotor motor drives the planetary gear to rotate through the outer ring gear
Implementation Method 3
The planetary carrier is rotatably connected with the hub through a bearing
Implementation Method 4
an outside of the bearing is further provided with an oil seal, and the oil seal is mounted between the hub and the bearing
Data Source
AI summary
A hub motor assembly includes a traveling wheel, an outer rotor motor and a deceleration mechanism. An inside of the traveling wheel is provided with an inner ring gear, the outer rotor motor is arranged inside the traveling wheel, and an outside of the outer rotor motor is provided with an outer ring gear. The deceleration mechanism includes a planetary carrier and at least one planetary gear, and the planetary carrier is arranged between the traveling wheel and the outer rotor motor. The planetary gear is rotatably mounted on the planetary carrier, and the planetary gear is internally meshed with the outer ring gear and externally meshed with the inner ring gear. The outer rotor motor drives the planetary gear to rotate through the outer ring gear, and the planetary gear drives the inner ring gear to rotate and then drives the traveling wheel to rotate.