Shift Actuator Pressure Modulation for Tooth-On-Tooth Gear Engagement
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Solution Overview
Problem
In automated manual transmissions, tooth-on-tooth positions at interlocking shifting elements can prevent gearshifts, as the shifting path cannot reach its end position, leading to unresolved engagements and torque transmission issues.
Innovation Solution
The method involves varying the control of a pressure-medium-activated shift actuator to reduce pressure force at the tooth-on-tooth position, using a control unit and computer program to manage pressure in the actuator's chambers, potentially assisted by external torque, to resolve the jammed state by reducing torque transmission and allowing the shifting claws to rotate freely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure force is increased to ensure positive engagement of the shifting element, then engagement reliability is improved, but tooth-on-tooth positioning risk increases
Solution Approach 1:
The patent applies periodic action by using oscillating movements of the shifting element to resolve tooth-on-tooth positions. When a tooth-on-tooth position is detected, the system generates oscillations in the shifting element through periodic pressure variations in the actuator, allowing the elements to gradually move out of the jammed position through repeated small movements rather than a single large force application.
Solution Approach 2:
The patent implements dynamics by transitioning from static high pressure engagement to dynamic pressure modulation. The system continuously adjusts pressure levels based on real-time feedback from position sensors, creating a dynamic control strategy that maintains engagement reliability while actively preventing and resolving tooth-on-tooth positions through adaptive pressure variations.
2Ease of operation
If pressure force is reduced to resolve tooth-on-tooth position, then shifting element can be freed, but engagement reliability deteriorates
Solution Approach 1:
The system uses periodic pressure applications and releases to resolve tooth-on-tooth positions while maintaining engagement reliability. Instead of sustained low pressure, the actuator applies periodic pressure pulses that create oscillating movements, gradually working the shifting element out of the jammed position while maintaining sufficient engagement force during non-oscillation periods.
Solution Approach 2:
The patent employs feedback control by continuously monitoring the position of the shifting element through sensors and adjusting pressure accordingly. When a tooth-on-tooth position is detected via position feedback, the system modifies pressure levels to resolve the jamming, then restores normal engagement pressure once the position corrects itself, thereby maintaining reliability throughout the resolution process.
3Productivity
If gearshift speed is increased to improve productivity, then transmission efficiency is improved, but tooth-on-tooth position occurrence increases
Solution Approach 1:
The system uses real-time position feedback to detect approaching tooth-on-tooth conditions during high-speed gearshifts and dynamically adjusts pressure to prevent jamming. The feedback control system monitors shifting element position continuously and modulates actuator pressure based on detected position trends, allowing high-speed operation while preventing tooth-on-tooth positioning through proactive pressure adjustments.
Solution Approach 2:
The patent applies dynamic pressure control that adapts to the speed of gearshift operations. During high-speed shifts, the system uses rapid pressure modulations that match the shifted speed, creating dynamic forces that guide the shifting element through the engagement process without settling into tooth-on-tooth positions, thereby maintaining both productivity and reliability.
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 effectively resolves tooth-on-tooth positions by reducing pressure force, enabling gear engagement and preventing jamming, thus ensuring smooth gear changes in automated manual transmissions.
Implementation Method 1
a pressure force prevailing at the tooth-on-tooth position is reduced
Implementation Method 2
the torque that can be transmitted by way of the tooth-on-tooth position is reduced
Data Source
AI summary
The present invention relates to a method for resolving a tooth-on-tooth position of a positive-locking shifting element of an automated manual transmission, in which gear steps of the automated manual transmission are changed by means of a pressure-medium-actuated shift actuator. If, during a change of a gear step of the automated manual transmission, a tooth-on-tooth position occurs at the interlocking shifting element, then the control of the pressure-medium-actuated shift actuator is varied in such manner as to resolve the tooth-on-tooth position. A control unit for carrying out the method is also disclosed.