Transmission Synchronization via Frictional Shifting Elements
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Solution Overview
Problem
Automatic transmission devices with positive-locking shifting elements face challenges in achieving shifting comfort and uninterrupted traction due to limitations in differential speed range and increased production costs and space requirements for synchronization.
Innovation Solution
The method involves activating the positive-locking shifting element by increasing the transmission capacity of a frictional shifting element, allowing synchronization without additional constructive synchronization devices, thereby enabling shifts with high comfort and no traction interruption within predefined times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If positive-locking shifting elements are used in automatic transmission devices, then drag losses are reduced and efficiency is improved, but shifting comfort deteriorates and shifting time increases due to limited differential speed range
Solution Approach 1:
A frictional shifting element is introduced as an intermediary component to mediate between the input and output shafts during the shifting process. This frictional element temporarily absorbs the differential speed difference, allowing the positive-locking shifting element to engage smoothly without direct冲击 loads, thereby maintaining both efficiency and shifting comfort
Solution Approach 2:
The frictional shifting element is activated in advance before the positive-locking shifting element engages. By pre-synchronizing the speed difference through frictional engagement, the system prepares the transmission for the subsequent positive-locking engagement, reducing shifting time and improving comfort
2Ease of operation
If additional constructive synchronization devices are added to positive-locking shifting elements, then shifting comfort is improved, but production costs and installation space requirements increase
Solution Approach 1:
The frictional shifting element serves multiple functions: it acts as a synchronization device during shifting, provides torque transmission during transition, and reduces mechanical loads on the positive-locking element. This multi-functionality eliminates the need for separate synchronization devices, reducing complexity and cost
Solution Approach 2:
The synchronization function is merged with the torque transmission function by using the same frictional shifting element for both purposes. This integration eliminates the need for additional constructive synchronization devices, thereby reducing production costs and installation space requirements
3Loss of time
If positive-locking shifting elements are engaged at high differential speeds, then shifting time is reduced, but mechanical loads increase and shifting comfort deteriorates
Solution Approach 1:
The shifting process is divided into periodic phases: first the frictional shifting element engages to reduce differential speed, then the positive-locking element engages to complete the shift. This periodic action allows the system to manage mechanical loads in stages, reducing peak loads while maintaining acceptable shifting time
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
This approach allows for cost-effective and space-efficient operation of transmission devices with positive-locking shifting elements, achieving high shifting comfort and low mechanical loads while maintaining uninterrupted traction during gear changes.
Implementation Method 1
at least one frictional shifting element, which is not to be switched on either to represent the current operating state of the transmission device or to represent the translation to be engaged, is activated at least approximately synchronized by increasing the transmission capacity
Data Source
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AI summary
Described is a method for operating a transmission device (1) comprising multiple frictionally engaged shifting elements (A, D, E, F) and at least one interlocking shifting element (B, C) to obtain various gears. When a gear change is requested, during which the interlocking shifting element (C) is moved from an unlocked into a locked operating state, the interlocking shifting element (C) is at least nearly synchronized by increasing the transmission capability of at least one frictionally engaged shifting element (A) that does not need to be connected to the power flow to obtain the gear to be disengaged or the gear to be engaged.