Nested Input Shaft Seven-Speed Transmission
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Solution Overview
Problem
Existing power transmitting apparatuses for vehicles face challenges in minimizing length to improve mountability and drivability while maintaining fuel economy, particularly in preventing distortion of step ratios which affects efficiency and fuel consumption.
Innovation Solution
A power transmitting apparatus with a variable connecting device using two clutches and input/output shafts with strategically positioned gears and synchronizer modules, allowing for efficient torque transmission and minimizing the number of input gears on the shafts to prevent elongation and optimize gear ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of input gears on the input shafts is increased to achieve more forward speeds, then the speed range and versatility are improved, but the shaft length increases and mountability deteriorates
Solution Approach 1:
The patent applies nesting by placing the second input shaft inside the first input shaft, with the second input shaft penetrating through the first input shaft. This nested configuration allows multiple input gears to be arranged along the penetrating portion of the second input shaft without increasing the overall shaft length, thereby achieving multiple forward speeds while maintaining compact dimensions for improved mountability
Solution Approach 2:
The patent utilizes the spatial dimension created by the nested shaft configuration to arrange input gears. By positioning gears along the penetrating portion of the second input shaft that passes through the first input shaft, the design transforms a one-dimensional length constraint into a two-dimensional spatial arrangement, enabling multiple gears without proportionally increasing shaft length
2Length of moving object
If the shaft length is minimized to improve mountability, then the compactness and ease of installation are improved, but the ability to maintain proper step ratios for drivability deteriorates
Solution Approach 1:
The nested shaft configuration enables the second input shaft to penetrate through the first input shaft, creating sufficient axial space within a compact overall length. This arrangement allows proper spacing between multiple input gears while maintaining a minimized shaft length, thereby preserving correct step ratios for optimal drivability without compromising compactness
Solution Approach 2:
The patent segments the input shaft system into two separate input shafts (first and second input shafts) that operate independently but are spatially integrated through nesting. This segmentation allows each shaft to carry specific gears (odd-numbered gears on the first shaft, even-numbered gears on the second shaft), enabling precise control over gear positioning and step ratio maintenance within a compact configuration
3Adaptability or versatility
If multiple gears are simultaneously engaged with the same input gear to achieve multiple speeds, then the speed versatility is improved, but the gear train complexity increases
Solution Approach 1:
The patent implements multi-functionality by designing certain input gears to serve multiple purposes. Specifically, the second input gear and third input gear are each simultaneously engaged by multiple speed gears (second and fourth speed gears engage with the second input gear; third and seventh speed gears engage with the third input gear). This universal engagement design allows a single input gear to control multiple speed ratios, achieving speed versatility while reducing the total number of gear engagement points and simplifying the overall gear train structure
Data Source
AI summary
A power transmitting apparatus for a vehicle achieves seven forward speeds with a minimal number of input gears disposed on input shafts, since the second speed gear and the fourth speed gear are simultaneously engaged with the second input gear and the third speed gear and the seventh speed gear are simultaneously engaged with the third input gear, and distortion of step ratios at the high-speed region may be prevented.