Wheel Isolator Coupling Axial Load Isolation
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Solution Overview
Problem
Prior art wheel isolator couplings transmit axial loads to sprocket bearings, leading to premature failure due to noise, vibration, and harshness (NVH) issues in motorcycle rear wheel drives.
Innovation Solution
A wheel isolator coupling design that imparts no axial force to the sprocket bearing, utilizing a sprocket assembly connected via a sprocket adaptor and wheel adaptor with elastic blocks to absorb and dissipate energy, eliminating direct axial force transmission through a single deep grooved ball bearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art couplings transmit axial loads from the sprocket to wheel shaft bearings, then the coupling structure is simple and direct, but the wheel bearings experience premature failure due to axial loads
Solution Approach 1:
The patent introduces a sprocket adaptor as an intermediary component between the sprocket and wheel shaft bearings. This adaptor features a special geometry with a spherical outer surface that contacts the bearing, while the inner surface receives the sprocket. The adaptor acts as a mediator that transforms the load transmission path, allowing radial loads to pass through while blocking axial loads from reaching the bearing, thus resolving the contradiction between simple structure and bearing reliability
Solution Approach 2:
The coupling is segmented into distinct functional components: the sprocket, the sprocket adaptor, and the wheel shaft bearing. This segmentation allows each component to be optimized for its specific function - the sprocket for power transmission, the adaptor for load transformation and isolation, and the bearing for smooth rotation. The segmentation enables the adaptor to specifically handle axial load isolation while maintaining overall structural efficiency
2Object-affected harmful factors
If vibration isolating materials are contained within the sprocket hub, then NVH reduction is achieved, but axial loads are transmitted to the bearings causing premature failure
Solution Approach 1:
The sprocket adaptor serves as a mediator that separates the vibration isolation function from the load transmission function. The adaptor's special geometry with spherical outer surface and axial bore creates a mechanical interface that blocks axial loads while allowing the vibration isolating materials in the sprocket hub to effectively reduce NVH transmission to the wheel shaft bearings
3Device complexity
If a single deep grooved ball bearing is used in the isolator coupling, then the device complexity is reduced and the isolator unit becomes self-contained, but the bearing must withstand axial loads that cause premature failure
Solution Approach 1:
The sprocket adaptor acts as a protective intermediary that shields the single deep grooved ball bearing from axial loads. The adaptor's geometry with spherical outer surface contacting the bearing and axial bore receiving the sprocket creates a load path that directs radial loads to the bearing while blocking axial loads, allowing the use of a simpler single bearing configuration without compromising reliability
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
Significantly reduces NVH during dynamic events like transmission speed shifting and hard launches, extending bearing lifespan and allowing for a self-contained, versatile isolator unit suitable for various motorcycle platforms.
Implementation Method 1
utilizing a sprocket assembly connected via a sprocket adaptor and wheel adaptor with elastic blocks to absorb and dissipate energy
Data Source
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AI summary
A wheel isolator coupling comprising a sprocket for engaging a drive member, the sprocket fixedly connected to a first adaptor, the sprocket rotationally engaged with a shaft through a first bearing, a wheel portion fixedly connected to a second adaptor, the wheel portion rotationally engaged with the shaft through a second bearing, the first adaptor having at least one receiving portion, at least one compressible member disposed within the receiving portion, the second adaptor having a radially extending member for engaging the compressible member within the receiving portion, and the sprocket imparting no axial force to the first bearing.