Transmission Interlocking Shifting Element Engagement Control
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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 wear, as existing methods rely on complex rotational speed gradient calculations that delay recognition of substantial changes and may result in irreversible damage if the closing process occurs outside the desired rotational speed difference window.
Innovation Solution
A method for operating a transmission device where the engagement process of interlocking shifting elements is discontinued if the rotational speed variation crosses a predefined threshold before reaching the synchronous speed, with optional forced engagement if the threshold is exceeded, and a timer is used to ensure safe disengagement if the process is prolonged, thereby avoiding damage and maintaining a safe operating condition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex rotational speed gradient calculations are used to determine lead time for closing interlocking shifting elements, then the control system can account for system delays, but the recognition of substantial rotational speed changes is delayed
Solution Approach 1:
The patent changes the control parameter from complex gradient calculations based on multiple rotational speed values to a simple threshold comparison of the current rotational speed difference. This allows immediate recognition when the synchronous point is approached without the computational delay of calculating gradients from multiple historical values.
Solution Approach 2:
The patent establishes a predetermined speed difference window before the synchronous point where the closing process should be initiated. This preliminary definition of the engagement window allows the control system to act immediately when conditions are met, without waiting for complex calculations to determine the optimal timing.
2Reliability
If the closing process is initiated with lead time before the synchronous point, then engagement success probability increases, but damage risk increases if the closing process occurs outside the desired rotational speed difference window
Solution Approach 1:
The patent continuously monitors the rotational speed difference and compares it against the predetermined threshold. This feedback mechanism ensures that the closing process is only initiated when the speed difference is within the safe window, preventing damage while ensuring successful engagement. The real-time monitoring provides immediate feedback to adjust the closing timing.
Solution Approach 2:
The patent makes the closing decision dynamic by continuously evaluating the current rotational speed difference against the threshold. Rather than using fixed lead times, the system adapts the closing initiation timing based on the actual real-time speed conditions, optimizing both success probability and damage prevention.
3Measurement precision
If multiple rotational speed values are used for gradient calculation, then measurement accuracy improves, but the complexity of the control system increases
Solution Approach 1:
The patent extracts only the essential information needed for control - the current rotational speed difference - and discards the complexity of using multiple historical values for gradient calculation. This simplification maintains measurement precision by focusing on the most relevant parameter while dramatically reducing computational requirements.
4Object-affected harmful factors
If the closing process is delayed until closer to the synchronous point, then damage risk decreases, but engagement success probability decreases due to insufficient lead time for hydraulic reaction
Solution Approach 1:
The patent defines a predetermined speed difference window that provides the necessary lead time for hydraulic reaction while keeping the closing initiation close enough to the synchronous point to ensure successful engagement. This preliminary setup of the threshold parameter balances both requirements without needing complex calculations.
Data Source
AI summary
A method of operating a transmission device having gears that are engaged by actuating shifting elements. At least one of the shifting elements is an interlocking shifting element which has to be engaged in at least one gear to transmit drive between an input and an output shaft. When a command is received to engage the interlocking shifting element, a rotational speed of the input shaft is displaced in the direction toward a synchronous rotation speed produced in the engaged operating condition of the interlocking shifting element at least as a function of the rotational speed of the output shaft. The engagement process of the interlocking shifting element from its disengaged operating condition is discontinued if, before reaching the synchronous rotational speed, the variation of the rotational speed of the input shaft crosses a predefined rotational speed threshold without initiating engagement of the interlocking shifting element.