Transmission Interlocking Shifting Element Speed Threshold Actuation
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Solution Overview
Problem
Interlocking shifting elements in transmission devices can suffer damage due to late initiation of closing processes, leading to unsuccessful engagement and potential damage when the rotational speed difference between shifting element halves is too large, and existing methods delay the recognition of substantial rotational speed changes.
Innovation Solution
A method for operating a transmission device where the interlocking shifting element is actuated when the rotational speed of the transmission input shaft crosses a predefined threshold, ensuring engagement within the necessary rotational speed difference window, and the engagement process is discontinued if the speed variation crosses additional thresholds, preventing damage and maintaining a safe operating condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the closing process of an interlocking shifting element is initiated with lead time before reaching the synchronous point, then the engagement can be completed within the rotational speed difference window, but the method may not recognize substantial rotational speed changes promptly due to complex calculation delays
Solution Approach 1:
The patent applies preliminary action by determining a lead time before the synchronous point is reached to initiate the closing process of the interlocking shifting element. This ensures that the engagement occurs within the rotational speed difference window while accounting for system delays in signal propagation, hydraulic reaction, and component travel path.
Solution Approach 2:
The patent dynamically adjusts the lead time based on the currently existing gradient of rotational speed variation. By continuously monitoring rotational speed changes and adapting the lead time accordingly, the system optimizes the timing of the closing process to account for varying operational conditions without requiring complex calculation methods that would delay response.
2Ease of operation
If the closing process is delayed until closer to the synchronous point, then the rotational speed difference is smaller facilitating engagement, but the risk of damage increases due to late initiation and inability to complete engagement within the speed window
Solution Approach 1:
The patent initiates the closing process in advance before the synchronous point is reached, ensuring that the interlocking shifting element has sufficient time to complete engagement within the rotational speed difference window. This preliminary action prevents damage by avoiding late initiation that would result in unsuccessful engagement attempts.
Solution Approach 2:
The patent continuously monitors the rotational speed of the transmission input shaft and compares it against the synchronous rotational speed. This feedback mechanism enables real-time detection of the approach to the synchronous point and triggers the closing process at the optimal moment, balancing engagement ease with damage prevention.
3Reliability
If complex calculation methods are used to determine gradients of rotational speed variations, then erroneous control commands are avoided, but substantial rotational speed changes cannot be recognized promptly
Solution Approach 1:
The patent dynamically adjusts the lead time parameter based on the gradient of rotational speed variation without employing complex calculation methods. By simplifying the determination of rotational speed changes and adapting the lead time accordingly, the system achieves prompt recognition of substantial speed changes while maintaining control accuracy.
Solution Approach 2:
The patent changes the lead time parameter as a function of the rotational speed variation gradient. This parameter adjustment allows the system to respond promptly to substantial rotational speed changes while still preventing erroneous control commands through appropriate lead time selection based on the current operational conditions.
Data Source
AI summary
A method of operating a transmission which is shifted to various operating conditions by engaging shifting elements. At least one of the shifting elements is an interlocking shifting element which has to be engaged to obtain at least one defined operating condition of the transmission during which power flows between an input and an output shaft. When a command is received to engage the interlocking shifting element, a rotational speed of the transmission input shaft is displaced in the direction toward a synchronous rotational speed produced in the engaged operating condition of the interlocking shifting element at least as a function of the rotational speed of the transmission output shaft. When the variation of the rotational speed of the transmission input shaft crosses a predefined rotational speed threshold, the interlocking shifting element is actuated in its engaging direction.