Motorcycle Engine Unit Swing Mechanism for Stability
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Solution Overview
Problem
Straddle-type vehicles face instability due to fluctuations in wheelbase caused by the short distance between the fulcrum and rear wheel axle, leading to variations in running stability with changes in rider weight or road conditions.
Innovation Solution
A straddle-type vehicle design where the crankshaft of the engine unit is positioned in the front, with a supported member attached to the pivot shaft before the crankshaft, increasing the distance between the pivot shaft and rear wheel axle, and incorporating a shock absorbing unit that expands and contracts around the pivot shaft to enhance stability and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the pivot shaft is attached to the intermediate portion of the engine unit, then stable support of the engine unit can be achieved, but the wheelbase easily varies and running stability deteriorates
Solution Approach 1:
The engine unit is divided into functionally distinct regions: the front portion (intermediate part) is attached to the pivot shaft for stable support, while the rear portion extends to the rear wheel axle. This segmentation allows the front to provide stable support and the rear to maintain appropriate wheelbase, resolving the contradiction between support stability and running stability.
2Volume of moving object
If the distance between the pivot shaft and rear wheel axle is short, then the engine unit can be compactly arranged, but the rotation angle becomes large and wheelbase fluctuates
Solution Approach 1:
The invention changes the key parameter of the distance between the pivot shaft and rear wheel axle to an appropriate length. By optimizing this distance parameter, the rotation angle of the engine unit is controlled to be not excessively large, thereby reducing wheelbase fluctuation while maintaining compact arrangement.
3Stability of the object's composition
If the supported member is positioned forward of the crank shaft, then wheelbase fluctuations are reduced, but the engine unit structure becomes more complex
Solution Approach 1:
The supported member positioned forward of the crank shaft serves multiple functions: it provides stable support for the engine unit, maintains appropriate wheelbase by controlling rotation angle, and acts as a structural integration point. This multi-functionality reduces wheelbase fluctuation without proportionally increasing complexity.
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 design reduces wheelbase fluctuations, improves running stability, and enhances operational feedback by allowing the engine unit to swing more effectively with the rear wheel, while the shock absorbing unit increases durability and reduces vibration.
Implementation Method 1
a shock absorbing unit which reduces vibration of the engine unit
Implementation Method 2
a shock absorbing unit that expands and contracts around the pivot shaft
Data Source
Figure 1
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AI summary
A motorcycle includes a pivot shaft (109) supported by a body frame (10), and an engine unit (20) which swings upward and downward with a rear wheel (3) with the fulcrum located at the pivot shaft (109). A crank shaft (34) is disposed before the engine unit (20). The engine unit (20) has supported members (22) disposed before the crank shaft (34) and attached to the pivot shaft (109). The rear part of the engine unit (20) supports an axle (4) of the rear wheel (3).