Three-Speed Motorcycle Transmission Synchronous Belt Efficiency
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Solution Overview
Problem
Current CVT transmissions in motorcycles suffer from low efficiency, especially during transient maneuvers due to hysteresis effects, leading to increased consumption and reduced overall vehicle efficiency.
Innovation Solution
A three-speed synchronous transmission system using toothed belts and pulleys with automatic synchronization, minimizing hysteresis and enhancing efficiency by eliminating sliding friction, while maintaining a comparable gear range to traditional CVT systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If CVT transmission with sliding type means is used, then continuous traction is provided and manual actuation of different ratios is not requested, but efficiency is low especially in transient maneuvers due to hysteresis effect
Solution Approach 1:
The continuous variable transmission is segmented into three distinct speed ranges, each handled by a dedicated synchronous belt drive stage. This segmentation eliminates the hysteresis losses inherent in continuous sliding mechanisms while maintaining automatic operation through the sequential engagement of three fixed ratio stages that collectively provide continuous variable transmission capability.
Solution Approach 2:
The transmission system changes the fundamental operating parameter from continuous sliding contact to discrete synchronous engagement. By using three synchronous belt drives with different fixed ratios instead of a single continuous variable mechanism, the system achieves high efficiency through positive engagement while still providing automatic transmission through the coordinated operation of the three stages.
2Loss of energy
If synchronous transmission with toothed belts is used, then efficiency is increased by reducing hysteresis effect, but device complexity increases compared to simple CVT systems
Solution Approach 1:
The patent merges three synchronous belt drive stages into a single integrated transmission system. By combining the three fixed ratio stages with automatic engagement mechanisms into one unified device, the complexity is managed while achieving high efficiency through synchronous engagement. The merged structure provides continuous variable transmission capability without requiring three separate transmission systems.
Solution Approach 2:
Each synchronous belt drive stage is designed to perform multiple functions: power transmission, ratio selection, and automatic engagement control. This multi-functionality reduces the overall component count and simplifies the structure compared to having separate mechanisms for each function, thereby reducing device complexity while maintaining high efficiency.
3Adaptability or versatility
If three fixed speed ratios are provided, then adequate range is guaranteed comparable to traditional CVT systems, but transmission structure becomes more complex than single-stage systems
Solution Approach 1:
The three synchronous belt drives are arranged in a nested configuration where the second belt drive is positioned within the space occupied by the first, and the third is positioned within the space of the second. This nesting arrangement provides three distinct speed ratios with adequate range comparable to traditional CVT systems while minimizing the overall structural footprint and reducing device complexity through space-efficient design.
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 provides high efficiency and automatic operation with performance similar to CVT systems, reducing energy consumption and improving overall transmission efficiency for urban transport.
Implementation Method 1
a first synchronous belt 11 extending between a first pulley 9, mounted on the crankshaft 2, and a second pulley 12 mounted on the primary shaft 3
Data Source
Figure 1~2
Figure 3A~3C
AI summary
A three-speed motorcycle transmission (1), to be used aboard a motorcycle as transmission means for 5 transmitting the motion generated by an engine to a driving wheel, having performances similar to those of a continuously variable transmission but, at the same time, a high efficiency and an easy automatic operation, comprises: a crankshaft (2), which receives the motion by 0 an engine, having a first pulley (9) mounted thereon; a primary shaft (4), having a second pulley (12) and a first set of three gears (21, 22, 23) mounted thereon; a transmission belt (11) connecting said first and said second pulley (9, 12); a secondary shaft (4), connected 5 to a driving wheel, comprising a second set of three gears (31, 32, 33), engaged in pairs with respective gears (21, 22, 23) of the first set of three gears for the transmission of the first, second and third speed; a clutch (10) acting selectively on at least two pairs of 0 gears assigned to the transmission of the second and third speeds; and two free wheels (15, 18) arranged at the pairs of gears assigned to the transmission of the first and second speed.