Automatic Transmission 10 Forward Gears Friction Loss
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Solution Overview
Problem
Existing automatic transmissions face inefficiencies due to high friction loss and decreased efficiency from multiple engagement mechanisms being engaged at each gear, particularly when attempting to achieve more than eight forward gears, leading to increased friction loss and reduced fuel efficiency.
Innovation Solution
The automatic transmission employs four single-pinion planetary gear mechanisms and seven engagement devices, including clutches and brakes, arranged to achieve 10 forward gears with fewer engagement mechanisms in use at each gear, reducing friction loss and improving efficiency by optimizing gear ratios and engagement states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple engagement mechanisms are engaged at each gear to achieve more forward gears, then the number of gears increases, but friction loss increases and efficiency decreases
Solution Approach 1:
The patent divides the engagement mechanisms into multiple independent sets, each responsible for specific gear ranges. This segmentation allows different engagement mechanisms to be engaged/disengaged independently, reducing the number of simultaneously engaged mechanisms and thereby reducing friction loss while maintaining multiple forward gears.
Solution Approach 2:
The patent employs dynamic engagement and disengagement of clutch mechanisms to optimize the number of engaged mechanisms at each gear. By dynamically controlling which engagement mechanisms are active at each gear position, the system minimizes friction loss while achieving 10 forward gears, thereby resolving the contradiction between gear multiplicity and energy efficiency.
2Adaptability or versatility
If multiple engagement mechanisms are engaged at each gear, then more gear ratios are achievable, but the complexity of the transmission system increases
Solution Approach 1:
The transmission system is segmented into multiple planetary gear mechanisms (first, second, and third planetary gear mechanisms) with dedicated engagement mechanisms for each. This modular segmentation allows complex gear ratios to be achieved through coordinated operation of simpler subsystems, reducing overall system complexity while maintaining versatility.
Solution Approach 2:
The engagement mechanisms are designed with multi-functionality, where each mechanism can serve multiple gear ratios across different ranges. This universality reduces the total number of engagement mechanisms needed, thereby reducing system complexity while still achieving 10 forward gears with varied ratios.
3Adaptability or versatility
If multiple engagement mechanisms are engaged at each gear, then more gear options are available, but fuel efficiency decreases
Solution Approach 1:
The system dynamically engages and disengages specific clutch mechanisms based on the selected gear position. By optimizing which engagement mechanisms are active at each gear, the system minimizes energy loss through friction while maintaining 10 forward gear options, thereby improving fuel efficiency without sacrificing gear versatility.
Solution Approach 2:
The patent changes the operational parameters of engagement mechanisms by adjusting engagement timing and duration. By optimizing when each engagement mechanism is activated and deactivated, the system reduces energy consumption and improves fuel efficiency while maintaining full gear option availability.
Data Source
AI summary
An automatic transmission includes an input shaft, first to fourth planetary gear mechanisms and first to seventh engagement devices. Ten forward gears of the automatic transmission are established by bringing at least three of the first to seventh engagement devices into an engagement state.