Shiftable Transmission Lever Alignment for Reduced Shift Load
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Solution Overview
Problem
The existing vehicle transmission systems experience inefficiencies in shifting operations due to an oblique angle of the shift rod, leading to poor operation sensation and increased load on the driver, as the shift rod is not aligned optimally with the operation lever and switching lever, resulting in significant loss of shifting force in the right-left direction.
Innovation Solution
The vehicle design positions the continuously variable transmission at the side of the engine, with the shiftable transmission and switching lever aligned on the same side, allowing the shift rod to be oriented along the front-rear direction, reducing the intersection angle and minimizing the right-left component force loss, thus optimizing the shifting operation force transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the shift rod is arranged obliquely to connect the operation lever and switching lever, then the transmission components can be compactly arranged, but the shifting operation force is significantly lost in the right-left direction, leading to poor operation sensation and increased driver load
Solution Approach 1:
The patent repositions the switching lever from a lateral arrangement to a longitudinal arrangement along the front-rear direction of the vehicle. This dimensional change in lever positioning allows the shift rod to be aligned with the operation lever's movement direction, eliminating oblique angle force loss while maintaining compact transmission component arrangement through optimized spatial configuration.
2Device complexity
If the switching lever is positioned based on transmission structure constraints, then the transmission can be compactly designed, but the shift rod must extend obliquely rearward, causing significant loss of shifting operation force
Solution Approach 1:
The patent introduces an intermediate positioning strategy where the switching lever is placed on the same side as the continuously variable transmission with respect to the shiftable transmission center. This intermediary positioning allows the shift rod to connect both levers along the front-rear direction, mediating between the transmission structure constraints and the force transmission requirements, thereby eliminating oblique angle force loss.
3Force
If the shift rod is made stronger to compensate for oblique angle force loss, then sufficient shifting force can be transmitted, but the overall system complexity and component strength requirements increase
Solution Approach 1:
The patent changes the geometric parameter of the shift rod's orientation from an oblique angle to a longitudinal alignment along the front-rear direction. This parameter change optimizes the force transmission efficiency, allowing the use of lighter, simpler shift rod components while still achieving sufficient shifting force transmission, thereby reducing overall system complexity and component strength requirements.
Data Source
AI summary
A vehicle includes an engine, a continuously variable transmission, a shiftable transmission, a switching lever, a shift rod, and an operation lever. The continuously variable transmission is located at a side of the engine. The shiftable transmission is located on the same side as the engine in a right-left direction with respect to the continuously variable transmission. The switching lever is located on the same side as the continuously variable transmission with respect to a center of the shiftable transmission in the right-left direction, and inputs a shifting operation force into the shiftable transmission. The shift rod is linked to the switching lever. The operation lever is operated by a driver seated on the seat to shift the shiftable transmission, and is linked to the shift rod.