9-Speed Transmission Form-Locking Shift Element Sensor Control
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Solution Overview
Problem
9-speed transmission devices face inefficiencies due to drag torques from friction-locking shift elements in disengaged states and potential mechanical or electrical malfunctions that prevent form-locking shift elements from disengaging correctly, leading to undefined operating states like overdetermined gear sets or unwanted power flow.
Innovation Solution
A method for operating a 9-speed transmission that includes a sensor device to detect the operating state of form-locking shift elements, generating a disengagement control signal and actuating the shift elements based on sensor feedback to ensure a safe operating state, preventing undefined states by distinguishing between engaged and disengaged states and using a timer to manage disengagement procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If friction-locking shift elements are used to implement transmission ratios, then the transmission device can be operated, but drag torques occur in the disengaged state which lower the overall efficiency of the transmission
Solution Approach 1:
The transmission device segments the shift elements into two distinct types: friction-locking shift elements and form-locking shift elements. Each type serves a specific function - friction-locking elements handle torque transfer during engagement, while form-locking elements provide mechanical locking in the disengaged state without causing drag torques. This segmentation allows the system to eliminate the drag torque problem while maintaining operational capability.
2Loss of energy
If form-locking shift elements are used to eliminate drag torques, then transmission efficiency is improved, but mechanical or electrical malfunctions can prevent correct disengagement leading to undefined operating states
Solution Approach 1:
The system implements a feedback mechanism using a sensor device that detects the operating state of form-locking shift elements. The sensor provides real-time information about whether the shift element is engaged or disengaged, allowing the control device to verify the actual state and detect malfunctions. This feedback loop ensures that undefined operating states are identified and can be addressed, thereby improving disengagement reliability.
Solution Approach 2:
The control device generates a disengagement control signal that actuates the form-locking shift element in the direction of disengagement before the actual disengagement is needed. This preliminary action ensures that the shift element is prepared for disengagement and reduces the risk of malfunction during the critical disengagement moment, thereby improving reliability.
3Reliability
If a sensor device is added to detect the operating state of form-locking shift elements, then undefined operating states can be prevented, but the device complexity increases
Solution Approach 1:
The sensor device serves multiple functions: it detects the operating state of form-locking shift elements, provides feedback to the control device for verifying disengagement, and enables the control device to detect malfunctions and prevent undefined operating states. By making the sensor multi-functional, the system achieves improved reliability without proportionally increasing complexity.
4Reliability
If the transmission device is transferred to a safe operating state by actuating all shift elements, then undefined operating states are prevented, but the transmission loses operational capability
Solution Approach 1:
The transmission device dynamically transitions between different operating states. When a malfunction is detected or an undefined operating state is identified, the system temporarily actuates all shift elements to enter a safe operating state, interrupting power flow. Once the malfunction is resolved or the system is reset, the transmission can resume normal operation by selectively actuating only the necessary shift elements, thereby maintaining productivity while ensuring safety.
Data Source
AI summary
A method of operating a transmission device. At least one of the shift elements is a form-locking shift element. A sensor is associated with the form-locking shift element which can determine an operating state of the form-locking shift element. When a request to disengage the form-locking shift element occurs, a disengagement control signal is generated and the form-locking shift element is actuated in the direction of disengagement, depending on the disengagement control signal. The transmission device is transferred to a safe operating state in which the transmission output shaft can rotate, when an actuating pressure that changes the operating state of the form-locking shift element is determined with the sensor, even though a disengagement control signal was not generated, and/or when the sensor is associated with at least two form-locking shift elements and the form-locking shift elements are subjected to actuating pressure to implement a requested operating state change.