E-bicycle Drive Unit Gearing Support for Compact Multi-stage Transmission
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Solution Overview
Problem
Existing drive units for electric bicycles face challenges in optimizing installation space and reducing weight, particularly in mid-mounted motor configurations.
Innovation Solution
A drive unit design featuring a coaxial drive and output shaft, an electric motor with a gearing device comprising at least two stages, and a housing with a gearing support that rotatably mounts gear wheels, utilizing anti-friction bearings and a plate-shaped gearing support to reduce weight and installation space, along with a planetary transmission and spur-gear transmission for a compact and lightweight structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a gearing device with multiple gear stages is implemented, then the gear ratio is improved, but the installation space and weight increase
Solution Approach 1:
The patent combines multiple gear stages (planetary gear stage and at least one additional gear stage) into a single integrated gearing device that is mounted on one common gearing support. This merging of multiple gear stages onto a single support structure reduces the overall installation space compared to having separate supports for each gear stage, while maintaining the high gear ratio achieved through the multi-stage configuration.
Solution Approach 2:
The gearing support serves multiple functions: it provides mounting for the planetary gear stage, mounting for additional gear stages, and structural support for the entire gearing device. This multi-functional design eliminates the need for separate support structures for each gear stage, thereby reducing installation space and component count.
2Productivity
If a gearing device with multiple gear stages is implemented, then the gear ratio is improved, but the weight of the drive unit increases
Solution Approach 1:
The patent merges multiple gear stages onto a single gearing support, which reduces the total amount of support structure material needed compared to having separate supports for each stage. This integration reduces the overall weight of the drive unit while maintaining the high gear ratio achieved through the multi-stage planetary and additional gear stage configuration.
3Volume of moving object
If a compact drive unit structure is implemented, then the installation space is reduced, but the assembly forces required increase
Solution Approach 1:
The patent segments the gearing device into modular components (planetary gear stage and additional gear stages) that can be assembled on a single gearing support. This segmentation allows for standardized mounting interfaces and bearing arrangements, which reduces the forces required for assembly compared to integrating all gears into a monolithic structure, while still achieving a compact overall configuration.
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 solution achieves a compact, lightweight, and rigid drive unit with reduced assembly forces and improved adjustability, while maintaining a high gear ratio and minimizing operating noise.
Implementation Method 1
For rotatably mounting the first gear wheel, an anti-friction or plain bearing for example is held in the bearing opening of the gearing support
Data Source
AI summary
Is it provided a drive unit for an electric bicycle, comprisingan electric motor with a motor shaft for externally power-operated generation of an additional driving torque by external force,a gearing device for coupling a motor shaft of the electric motor to an output shaft, wherein the gearing device comprises at least two gear stages, anda housing accommodating the electric motor and the gearing device.The drive unit comprises a gearing support fixed in the housing), on which gearing support at least one gear wheel of a first gear stage and at least one gear wheel of a second gear stage are rotatably mounted.