Automatic Transmission Single-Pinion Planetary Gear Friction Loss
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Solution Overview
Problem
Existing automatic transmissions face inefficiencies due to high friction loss and complex gear engagement mechanisms, particularly in high-speed gear ranges, which affect transmission efficiency and fuel consumption.
Innovation Solution
The implementation of a single-pinion planetary gear system configuration with a reduced number of engagement mechanisms, utilizing wet multi-disc clutches and meshing mechanisms, and a one-way clutch to minimize friction loss and optimize gear shifting, allowing for forward nine-speed gear shifts with reduced disengaged mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple engagement mechanisms are used to achieve forward 8-speed transmission, then gear shifting capability is improved, but friction loss increases and transmission efficiency decreases
Solution Approach 1:
The patent extracts and eliminates unnecessary engagement mechanisms from the transmission system. By using a single-pinion planetary gear system instead of multiple planetary gear systems, the invention reduces the number of engagement mechanisms required while maintaining forward 8-speed transmission capability, thereby reducing friction loss and improving transmission efficiency.
Solution Approach 2:
The patent merges multiple planetary gear systems into a single-pinion planetary gear system. This consolidation integrates the functions of multiple engagement mechanisms into one unified system, reducing the total number of moving parts and engagement points, which directly reduces friction loss while preserving gear shifting capability.
2Adaptability or versatility
If multiple planetary gear systems are used to achieve multiple gear shifts, then gear shifting range is improved, but device complexity increases
Solution Approach 1:
The patent extracts unnecessary planetary gear systems from the transmission architecture. By eliminating redundant planetary gear systems and retaining only a single-pinion planetary gear system, the invention simplifies the overall device structure while maintaining the ability to achieve forward 8-speed transmission through optimized engagement mechanism control.
Solution Approach 2:
The single-pinion planetary gear system is designed to perform multiple functions that previously required separate planetary gear systems. By making this single system multi-functional, it can achieve various gear ratios and transmission modes, reducing device complexity while preserving gear shifting range.
3Ease of operation
If wet multi-disc clutches and brakes are used for engagement, then gear shifting smoothness is improved, but friction loss increases
Solution Approach 1:
The patent converts the harmful effect of friction into a beneficial control mechanism. By using wet multi-disc clutches and brakes, the invention utilizes friction in a controlled manner to achieve smooth gear shifting, while the reduced number of such components minimizes overall friction loss. The friction that remains is strategically applied only where needed for smooth engagement.
Data Source
AI summary
An automatic transmission includes an input shaft, an output member, a first planetary gear system, a second planetary gear system, a third planetary gear system, a fourth planetary gear system, and an engagement mechanism. The input shaft is configured to be rotated with power of a driving source relative to the transmission case. The output member is to output rotation of the input shaft using multiple gear-shifting. The multiple gear-shifting is provided by setting at least three of first to third clutches and first to third brakes in a connection state.