Automatic Gearbox Neutral Position Torque Lock Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automatic transmissions with increasing numbers of gears face challenges in securing the neutral position against undesired torque or frictional engagement, which could lead to unintentional vehicle movement.
Innovation Solution
The method involves ensuring that at least one shifting element engaged in the forward or reverse gear is completely open in the neutral position, with various alternatives to achieve comprehensive protection, including fully opening all closed elements, partially filling one, or locking two while opening the third, to prevent torque engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple shifting elements are engaged in each gear to enable comprehensive torque transmission, then the transmission can operate in multiple gears including reverse gear, but the transmission cannot be securely protected in neutral position against undesired torque engagement
Solution Approach 1:
The patent divides the shifting elements into functionally independent groups: some shifting elements (first group) are engaged/disengaged for forward gears, while other shifting elements (second group) are engaged/disengaged for reverse gear. This segmentation allows independent control of torque transmission paths, enabling secure neutral position by disengaging the appropriate group while maintaining gear operation capability.
Solution Approach 2:
The patent inverts the conventional approach by having different shifting elements engaged for forward versus reverse gear operation. Instead of using the same shifting elements for both directions, the system engages shifting elements from the first group for forward gears and shifting elements from the second group for reverse gear, allowing comprehensive protection in neutral position.
2Reliability
If all shifting elements are opened in neutral position to prevent torque engagement, then the transmission is secured against undesired movement, but the reaction time for gear engagement is delayed
Solution Approach 1:
By segmenting shifting elements into separate groups for forward and reverse operations, the patent allows only the relevant group to be disengaged for neutral position security, while the other group remains engaged and ready. This reduces the number of shifting elements that need to be actuated during gear engagement, thereby reducing response time.
Solution Approach 2:
The patent maintains shifting elements in a pre-engaged state for their respective gear types (forward or reverse). When a gear change is requested, the system only needs to disengage the currently active group and engage the target group, rather than engaging all shifting elements from a completely disengaged state, thus reducing engagement time.
3Device complexity
If the same shifting elements are used for both forward gear and reverse gear, then the transmission structure is simplified, but comprehensive protection in neutral position cannot be achieved
Solution Approach 1:
The patent segments shifting elements into distinct groups based on their functional assignment (forward gear group vs. reverse gear group). This segmentation provides comprehensive neutral position security by allowing independent disengagement of the active group, while the overall device complexity remains manageable through systematic organization and control logic.
Data Source
Figure 1~2
AI summary
The invention relates to a method for operating an automatic gearbox of a motor vehicle, in particular a variable automatic gearbox. Said automatic gearbox comprises at least five shifting elements. At least three shifting elements are closed for transmitting torque and/or force in a forward gear and in a reverse gear. According to the invention, at least one of the shifting elements, which is closed in the respective forward gear or reverse gear, is completely open in a neutral position of the automatic gearbox for preventing un-desired torque lock and/or force lock.