Multi Sprocket Welding for Compact Bicycle Gear Systems
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Solution Overview
Problem
The increasing number of sprockets in bicycle multi-sprocket arrangements poses challenges due to limited installation space and difficulties in economic production, particularly for small sprockets with a small tooth difference, where traditional push-fit connections are impractical.
Innovation Solution
A multi-sprocket arrangement where adjacent sprockets with different numbers of teeth are connected by welding, with one sprocket having a larger inner diameter than the driver's profile base and another with a smaller inner diameter, allowing for compact and economic production, and utilizing flange portions for easy welding access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of sprockets is increased to expand the translation ratio, then the drive spread is improved, but the installation space becomes restricted
Solution Approach 1:
The patent transitions from a single-plane sprocket arrangement to a multi-dimensional configuration where sprockets are stacked axially on the driver. This vertical stacking in the axial dimension allows more sprockets to be accommodated within the radial space constraints, effectively increasing the translation ratio without proportionally increasing the installation footprint.
Solution Approach 2:
Multiple sprockets are nested axially on the same driver shaft, with each sprocket positioned at a different axial location. This nesting arrangement allows the sprocket package to utilize the axial dimension of the installation space, enabling a higher number of sprockets to be accommodated within the available radial and axial boundaries defined by the hub driver limit stop and frame limit stop.
2Ease of manufacture
If traditional push-fit connection is used for assembling sprockets, then assembly is simplified, but it becomes impractical for small sprockets with small tooth difference
Solution Approach 1:
The patent replaces the mechanical push-fit connection system with a welding connection system. This substitution eliminates the need for radial clearance and opening space, allowing sprockets with very small tooth differences (including those with only 1-2 tooth differences) to be reliably connected. The welding process creates a permanent, strong bond that is particularly suitable for the narrow radial dimensions of small sprockets where push-fit connections would be impossible.
3Reliability
If welding connection is used for small sprockets, then connection reliability is improved, but the complexity of the connection process increases
Solution Approach 1:
The sprockets are designed with pre-formed flange portions that extend axially from the sprocket body. These flanges are created during the sprocket manufacturing process, so that when sprockets are stacked axially on the driver, the flanges automatically position the sprockets for welding. This preliminary preparation eliminates the need for complex positioning fixtures or alignment mechanisms during the welding assembly process, reducing the overall complexity despite the use of welding.
4Area of stationary object
If sprockets are made with small inner diameter to fit tight spaces, then space utilization is improved, but the material height in radial direction is reduced
Solution Approach 1:
The patent divides the sprocket structure into two distinct segments: the sprocket body with its small inner diameter for space efficiency, and the separately formed flange portion that provides the welding surface. This segmentation allows the sprocket body to maintain its compact radial dimensions while the flange extends axially to provide sufficient material height and surface area for reliable welding connections, effectively decoupling the space utilization requirement from the connection requirement.
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
This solution enables the production of a compact, economically viable multi-sprocket arrangement that fits within the limited space constraints, maintaining the dimensions of integrally produced sprockets while simplifying the welding process and ensuring effective torque transmission.
Implementation Method 1
The first sprocket and the second sprocket are connected together by welding
Data Source
AI summary
A multi sprocket arrangement is configured for mounting on a driver of a bicycle wheel. The multi sprocket arrangement includes a plurality of adjacent sprockets each of the plurality of sprockets having a different number of teeth. The plurality of adjacent sprockets include a first sprocket having a first inner diameter which is larger than an outer diameter of a profile base of a carrier profile of the driver, and a second sprocket having a second inner diameter which is smaller than the outer diameter of the profile base of the carrier profile of the driver. The first sprocket and the second sprocket are connected together by welding.