Coaxial E-Bike Power Module for Compact Dual-Power Transmission
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Solution Overview
Problem
The design of power modules for electric assisted bicycles faces challenges in optimizing space utilization and meeting the coexistence of dual powers (manpower and motor-assisted power) to enhance performance across different usage scenarios.
Innovation Solution
A concentrically arranged and mid-mounted power module is designed, featuring a gear-plate-output shaft with multiple sections of different diameters, one-way bearings, and a coaxial structure that includes a pedal shaft, gear-plate-output shaft, reducer-output shaft, and motor-output shaft. This configuration optimizes space and meets the output requirements of dual powers, while encoders provide precise driving and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional power module design is used, then the structure is simple, but the space utilization is poor and the volume is large
Solution Approach 1:
The patent implements a nested coaxial structure where the pedal shaft, gear-plate-output shaft, reducer-output shaft, and motor-output shaft are arranged concentrically along the same axis. This nesting arrangement allows multiple functional components to occupy the same spatial envelope, dramatically reducing the overall volume of the power module while maintaining all necessary functional pathways for dual power transmission.
Solution Approach 2:
The patent transitions from a conventional parallel or side-by-side arrangement of power transmission shafts to a coaxial arrangement along the axial dimension. By utilizing the radial dimension for layering multiple shafts concentrically, the design achieves compact space utilization without compromising the functional independence of each power transmission path.
2Adaptability or versatility
If dual power sources (manpower and motor) are integrated, then the functionality is enhanced, but the space requirement increases
Solution Approach 1:
The patent divides the power transmission system into distinct functional segments: the pedal shaft for manpower input, the motor-output shaft for motor power input, the reducer-output shaft for gear reduction, and the gear-plate-output shaft for final power output. Each segment is assigned a specific function, allowing independent optimization of each power path while maintaining compact integration through the coaxial arrangement.
Solution Approach 2:
The gear-plate-output shaft serves as a universal output component that receives power from both the pedal shaft (through one-way bearings) and the reducer-output shaft (through another one-way bearing). This multi-functional component consolidates the output functions of both power sources into a single shaft, enabling dual power coexistence without requiring separate output mechanisms that would increase volume.
3Productivity
If one-way bearings are used for dual power transmission, then the performance under different usage scenarios is optimized, but the device complexity increases
Solution Approach 1:
The patent employs one-way bearings (overrunning clutches) at critical junctions to enable dynamic power path selection. These bearings automatically engage or disengage based on the direction of torque application, allowing the system to adaptively route power from the pedal shaft or motor-output shaft to the gear-plate-output shaft depending on the current usage scenario, thereby optimizing performance without complex control mechanisms.
Data Source
AI summary
A power module of an electric assisted bicycle is disclosed and includes a pedal shaft, a gear-plate-output shaft, a reducer-output shaft and a motor-output shaft. The pedal shaft is arranged along an axial direction. The gear-plate-output shaft includes a first section and a second section arranged in the axial direction. The first section is concentrically sleeved on the pedal shaft through a first one-way bearing along a radial direction. When the pedal shaft is forced to rotate, the gear-plate-output shaft is driven through the first one-way bearing. The reducer-output shaft is concentrically sleeved on an outer surface of the second section through a second one-way bearing along the radial direction. The motor-output shaft is concentrically sleeved on the reducer-output shaft along the radial direction. When the motor-output shaft drives the reducer-output shaft to rotate, the gear-plate-output shaft is driven by the reducer-output shaft through the second one-way bearing.