Bicycle Drive Unit Swing Arm with Multi-Joint Linkage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing two-wheeler frame arrangements, particularly in bicycles, suffer from discomfort and safety issues due to varying distances between the saddle and bottom bracket, leading to changes in leg angle and potential loss of foot contact with the pedal, especially during compression or rebound movements.
Innovation Solution
A frame arrangement featuring a powertrain swing arm pivotally connected to the main frame via a multi-joint arrangement, maintaining a constant distance between the pedal crank and rear wheel hub, utilizing a four-bar linkage to provide stable pivoting mobility and incorporating a spring-damper assembly for damping, ensuring comfort and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bicycle drive unit is pivotally connected to the frame with a rigid pivot axis to enable suspension movement, then the suspension can compress and rebound, but the distance between the saddle and bottom bracket changes, causing leg angle variation and potential loss of foot contact with the pedal
Solution Approach 1:
The patent applies a multi-link arrangement instead of a rigid pivot axis, allowing the drive unit to move dynamically through multiple degrees of freedom. This enables the suspension to compress and rebound while the crank arm maintains a more stable position relative to the saddle, preventing leg angle variation and ensuring continuous foot contact with the pedal during suspension movement
Solution Approach 2:
The drive unit is divided into separate linkages (multi-link arrangement) rather than being a rigid integrated unit. This segmentation allows different parts of the drive unit to move independently, enabling the suspension function while maintaining stable crank arm positioning relative to the saddle
2Ease of operation
If the crank arm is positioned at a distance from the pivot axis to enable pedaling, then the pedal crank drive can function, but the crank arm pivots along with the suspension during compression or rebound, altering the distance between the saddle and bottom bracket
Solution Approach 1:
The multi-link arrangement creates a dynamic system where the crank arm's position is stabilized through the kinematic constraints of the linkage, allowing it to maintain a consistent position relative to the saddle even as the suspension moves, thereby maintaining stable pedaling geometry during compression and rebound
Solution Approach 2:
The multi-link arrangement acts as an intermediary mechanism between the suspension movement and the crank arm. It mediates the motion transmission, allowing the suspension to move while the crank arm remains relatively stable in position, thus decoupling the suspension motion from direct crank arm pivoting
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 maintains a constant pedal crank position relative to the rider, preventing unpleasant pedal impacts and enhancing comfort and safety by minimizing changes in the pedal crank's position during movement, allowing for independent pre-assembly and use across various frame designs.
Implementation Method 1
a spring-damper assembly for damping the pivoting movement of the drive unit swing arm relative to the main frame
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a frame assembly for a two-wheeled vehicle, in particular for a bicycle, comprising: a main frame (21), which comprises a head tube (22) for connecting to a front wheel mount (23) and a saddle connection (24) for connecting to a saddle (25); and a drive-train swingarm (30) pivotably connected to the main frame (21), wherein the drive-train swingarm (30) comprises a wheel suspension (31) for a rear wheel (11) to be driven and a pedal-crank drive having a pedal crank (32) for driving the rear wheel (11) by means of muscle force of a rider, which pedal-crank drive is associated with the drive-train swingarm (30). The drive-train swingarm (30) is pivotably connected to the main frame (21) by means of a multi-joint assembly (40). The invention further relates to a two-wheeled vehicle, in particular a bicycle or electric bicycle, wherein the two-wheeled vehicle comprises a corresponding frame assembly.