Harmonic Deceleration Module for Compact E-Bike Power Transmission

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Solution Overview

Problem

Conventional dynamic power devices used in electric bicycles are bulky, affecting the aesthetics and overall design of the vehicles.

Innovation Solution

A harmonic deceleration module comprising a connecting member, flexible bearing, flexspline, and circular splines that work together to decelerate dynamic power input, reducing the module's size while maintaining efficient power transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional speed reducers are used in dynamic power devices, then reliable power transmission is achieved, but the device size becomes bulky

Engineering Contradiction:

Improvepower transmission reliabilityVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent employs nested harmonic deceleration mechanisms where multiple circular splines (first circular spline, second circular spline) and flexsplines are nested within each other. The flexspline engages with both circular splines simultaneously, creating a compact nested structure that achieves high deceleration ratios in a small volume while maintaining reliable power transmission.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes dynamic flexible bearings that can elastically deform to accommodate the varying engagement positions of the flexspline with the circular splines. This dynamic flexibility allows the mechanism to maintain smooth power transmission while achieving compact dimensions, resolving the contradiction between reliability and size.

Inventive Principle:

Principle #15Dynamics

2Shape

If the deceleration module size is reduced, then aesthetic appeal is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveaesthetic appealVSAvoidmanufacturing complexity

Core Design Contradiction:

ShapeVSEase of manufacture

Solution Approach 1:

The patent divides the deceleration mechanism into modular segments including separate connecting members, flexible bearings, flexsplines, and circular splines. Each component can be manufactured independently using standard machining processes, then assembled together. This segmentation maintains manufacturing ease while achieving the compact shape needed for aesthetic appeal.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs flexible bearings with thin-walled structures that can elastically deform. These flexible components are manufactured using specialized forming processes that create the necessary flexibility while maintaining structural integrity. The use of flexible thin-walled structures enables compact design without significantly increasing manufacturing complexity.

Inventive Principle:

Principle #30Flexible shells and thin films

3Power

If conventional harmonic deceleration modules are used, then power deceleration is achieved, but the module size remains large

Engineering Contradiction:

Improvepower deceleration capabilityVSAvoidmodule size

Core Design Contradiction:

PowerVSVolume of moving object

Solution Approach 1:

The patent implements a nested configuration where the flexspline is positioned between two circular splines, with all components sharing a common central axis. This nested arrangement enables high deceleration ratios to be achieved in a compact cylindrical volume, significantly reducing module size while maintaining power deceleration capability.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes the radial dimension efficiently by arranging multiple gear-like components (flexspline, first circular spline, second circular spline) at different radial positions around a central axis. This three-dimensional arrangement allows power deceleration to be achieved in a compact footprint by exploiting the radial space, reducing the overall module size.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 results in a more compact dynamic power device that enhances the aesthetic appeal of electric bicycles while maintaining effective power transmission, with reduced vibration noise and improved dynamic characteristics.

Implementation Method 1

the wave generator drives the flexspline to continually and flexibly deform

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS12104686B2Dynamic power device, automatic mobile vehicle, transfer apparatus, dynamic power supply system, and electric bicycle

Publication Date: 2024.10.01 MAIN DRIVE CORP

AI summary

A harmonic deceleration module, a dynamic power device, an automatic mobile vehicle, a transfer apparatus, a dynamic power supply system, and an electric bicycle are provided. The harmonic deceleration module includes a connecting member, a flexible bearing, a first frame, a first circular spline, a second frame, and a second circular spline. When the connecting member is driven, the connecting member rotates around a central axis. The connecting member has a cam part, and the cam part and the flexible bearing jointly form a wave generator. The wave generator is configured to be driven by the connecting member to drive a flexspline to continually and flexibly deform, and the flexspline drives the second circular spline and the second frame connected to the second circular spline to rotate. The second frame has a hollow channel penetrating through the second frame along the central axis.