Rear Wheel Sprocket Assembly With Elastic Latching Strength
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Solution Overview
Problem
The existing bicycle rear wheel sprocket arrangements face mechanical stress and potential damage due to the large difference in tooth numbers and diameters between sprockets, leading to bending effects and stress peaks, which compromises the mechanical strength and stability during operation.
Innovation Solution
A bicycle rear wheel sprocket arrangement with a first partial arrangement comprising the largest sprocket and a second partial arrangement of integrally formed sprockets, secured by elastically deformable latching formations that engage with mating latching formations, preventing axial separation and enhancing mechanical strength without weakening components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the largest sprocket is made with a large diameter to accommodate the chain in positive-locking engagement, then the chain can be securely engaged, but the sprocket is subjected to considerable bending effects and mechanical stress that can cause damage
Solution Approach 1:
The sprocket arrangement is divided into a first partial arrangement comprising the largest sprocket and a second partial arrangement comprising other sprockets. This segmentation allows the largest sprocket to be optimized for chain engagement while the overall structure distributes mechanical stresses across multiple components, reducing the bending effects on any single sprocket.
2Strength
If fastening pins are pressed into fastening openings to connect partial arrangements, then the partial arrangements are securely connected, but the fastening openings weaken the fastening surfaces causing stress peaks and crack formation
Solution Approach 1:
Instead of creating openings in the fastening surfaces and inserting pins (which weakens the surfaces), the invention inverts the approach by having the fastening surfaces remain intact and using the latching formations to achieve secure connection. The latching formations engage with the fastening surfaces without compromising their structural integrity.
3Adaptability or versatility
If the sprocket arrangement has a large spread in the number of teeth between smallest and largest sprocket, then the gear ratio range is increased, but the difference in diameters causes the largest sprocket to be subject to considerable mechanical stress
Solution Approach 1:
By segmenting the sprocket arrangement into multiple partial arrangements, the invention allows for a large gear ratio range while distributing the mechanical stresses. The largest sprocket can be optimized for its specific function while the segmented structure prevents stress concentration that would occur in a monolithic design with such a wide tooth count spread.
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 latching engagement secures the partial arrangements together, transmitting forces effectively while distributing loads uniformly, thereby increasing the mechanical strength and stability of the sprocket arrangement, reducing the risk of damage and improving operational reliability.
Implementation Method 1
one of which has a plurality of elastically deformable latching formations, which are in latching engagement with a plurality of mating latching formations of the other partial arrangement
Data Source
AI summary
A bicycle rear wheel sprocket arrangement which is rotatable about a common sprocket rotation axis that defines an axial direction and orthogonal to which are radial directions, comprising a plurality of sprockets of different sizes and number of teeth arranged coaxially along the sprocket rotation axis, which are connected to one another such that the sprockets jointly rotate about the sprocket rotation axis together, wherein the sprocket arrangement comprises a first partial arrangement that includes a largest sprocket, and a second partial arrangement that includes a plurality of sprockets formed integrally with one another. One partial arrangement has a plurality of elastically deformable latching formations that are in latching engagement with a plurality of mating latching formations of the other partial arrangement to prevent the two partial arrangements from separating in the axial direction.