Electric Transmission Shift Control for Tooth-to-Tooth Blocking
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Solution Overview
Problem
Electrically shiftable transmissions in commercial vehicles face issues with noise and impaired functionality due to impacts and uncontrolled movements of switching elements, particularly in tooth-to-tooth positions, which existing technologies have not adequately addressed.
Innovation Solution
A method that determines boundary conditions for switching elements, including position, speed, and acceleration, to create a movement profile that controls the switching element's position over time, reducing noise and impact speeds, and optimizing the switching process by defining a polynomial relationship between position and time, thereby avoiding uncontrolled movements and tooth-to-tooth blocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a target position is set for the electric shift actuator to move the shifting element, then the shifting element reaches the target position, but this can result in an impact upon reaching the target position or blockage in tooth-to-tooth position, leading to noise and impaired transmission function
Solution Approach 1:
The patent applies dynamics by transitioning from static positioning (simple target position setting) to dynamic motion profile control. The control unit generates time-dependent motion profiles that define position, velocity, and acceleration throughout the shifting process, allowing the system to adapt the shifting element's movement characteristics in real-time to avoid impacts and noise while maintaining positioning precision.
Solution Approach 2:
The patent implements preliminary action by pre-calculating and storing multiple motion profiles in the control unit before the shifting operation begins. These profiles are prepared in advance with optimized velocity and acceleration characteristics, and the control unit selects and applies the appropriate profile based on the current shifting requirements, preventing noise and blockage before they occur.
2Productivity
If the shifting element moves quickly to reach the target position, then the shifting speed increases, but this can cause impact and noise emissions
Solution Approach 1:
The patent uses dynamics to create motion profiles that optimize the balance between shifting speed and noise reduction. The control unit generates time-dependent velocity profiles that allow rapid positioning while incorporating acceleration and deceleration phases that prevent impacts. The system dynamically adjusts the shifting element's speed throughout the movement trajectory rather than maintaining constant high speed.
Solution Approach 2:
The patent applies parameter changes by modifying the velocity and acceleration parameters of the shifting element during the shifting process. The control unit varies these parameters according to pre-calculated motion profiles, increasing speed during safe zones and reducing it during critical phases (such as approaching the target position or passing through tooth-to-tooth positions), thereby achieving both high productivity and low noise emissions.
3Object-generated harmful factors
If a complex motion profile with multiple parameters is used to control the shifting element, then noise and impact are reduced, but the control system complexity increases
Solution Approach 1:
The patent reduces control system complexity through preliminary action by pre-calculating and storing multiple motion profiles in the control unit's memory before operation. Each profile contains pre-determined position, velocity, and acceleration data for specific shifting scenarios. During operation, the control unit simply selects and executes the appropriate pre-prepared profile, avoiding the need for complex real-time calculations while still achieving precise control and noise reduction.
Solution Approach 2:
The patent applies mechanics substitution by replacing complex mechanical control mechanisms with an electronic control system that uses pre-stored motion profiles. Instead of using complex mechanical linkages or manual adjustment mechanisms to control velocity and acceleration, the system uses electronic control signals based on pre-calculated profiles, simplifying the physical control architecture while maintaining precise control over the shifting element's motion.
Data Source
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AI summary
Method (100) for switching an electrically switchable transmission (230) for a vehicle (200a), in particular a commercial vehicle (200b), wherein the method (100) comprises: determining (110) a boundary condition (310) relating to a switching element (235) of the transmission (230); determining (120) a motion profile (300) for the switching element (235), wherein the motion profile (300) defines a position (P) of the switching element (235) as a function of a time (t); and outputting (130) a control signal (255) for controlling the position of the switching element (235) based on the motion profile (300).