Electric Gearbox Shift Control Using Oscillation to Release Jamming
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Solution Overview
Problem
Existing electrically switchable gear systems for commercial vehicles often encounter blocking positions due to 'sticking' between switching elements, leading to increased switching time, reduced service life of gear components, and high mechanical stresses.
Innovation Solution
A procedure for switching an electrically switchable gear involves determining a control signal that defines a target size and oscillation for the movement of the switching element, allowing for dynamic force generation between switching elements to dissolve or avoid blocking positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If force is increased to move the shifting element to release a jammed position, then the shifting element can be released from locking position, but high mechanical stresses are generated causing complex transmission design
Solution Approach 1:
The patent applies mechanical vibration by superimposing an oscillating component on the control signal to the switching actuator. This causes the switching element to vibrate during the shifting process, which helps to break free from locking positions without requiring high static forces. The oscillation creates dynamic movement that prevents the switching elements from sticking together, thereby releasing jammed positions while avoiding excessive mechanical stress on the transmission components.
Solution Approach 2:
The patent implements periodic action through the oscillating component in the control signal. This periodic oscillation is superimposed on the target position during the shifting process, creating a rhythmic back-and-forth movement of the switching element. This periodic movement helps to overcome static friction and locking positions between switching elements, enabling reliable shifting without sustained high forces that would cause mechanical stress.
2Reliability
If force is increased to move the shifting element, then shifting can be accomplished, but switching time is increased due to force increase, release, and re-attempt
Solution Approach 1:
By applying mechanical vibration through the oscillating control signal component, the switching element continuously micro-moves during the shifting process. This prevents the switching elements from settling into locking positions, thereby avoiding the need to release and re-attempt shifts. The vibration ensures smooth, continuous movement through the shifting zone, reducing total switching time while maintaining reliable shifting completion.
Solution Approach 2:
The patent applies preliminary action by superimposing the oscillating component on the control signal before and during the shifting process. This preliminary oscillation prepares the switching element for smooth movement by preventing locking positions from forming in the first place. By proactively preventing sticking rather than reactively releasing it, the system avoids time-consuming force cycles and achieves faster switching.
3Strength
If complex and elaborate transmission design is used to withstand high forces, then transmission components can handle shifting forces, but device complexity increases
Solution Approach 1:
The patent replaces the traditional mechanical approach of designing robust components to withstand high forces with a control-based approach. Instead of relying on mechanically strong components to handle high shifting forces, the system uses an electronically controlled actuator with an oscillating control signal to achieve smooth, low-stress shifting. This substitutes complex mechanical reinforcement with a simpler electronic control strategy, reducing transmission design complexity while maintaining component strength.
4Reliability
If oscillation is added to control signal, then blocking positions are dissolved, but control complexity increases
Solution Approach 1:
The patent merges the oscillating component with the target position control signal in a unified control approach. Rather than treating oscillation as a separate complex control mechanism, it integrates the oscillation directly into the position control signal that already exists in the system. This merging allows the control unit to generate both the target position and the oscillating component using the same actuator control infrastructure, thereby resolving blocking positions without significantly increasing control complexity.
Data Source
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Figure 3
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: detecting (110) a state (237) of the switching element (235) relating to a locking position (231) of a switching element (235) of the transmission (230); determining (120) a control signal (255) for controlling a movement of the switching element (235) taking into account the state (237) and/or the locking position (231), wherein the control signal (255) defines a target variable (Z) of the movement of the switching element (235) and an oscillation (O) around the target variable (Z); and outputting (130) the control signal (255) for moving the switching element (235) based on the control signal (255).