Electronically Actuated Locking Differential With Armature Lock Detection
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Solution Overview
Problem
Existing differential gear mechanisms with locking functions often fail to provide real-time detection of the lock state, leading to potential unintended locking after de-energizing the electromagnetic coil, which can go unnoticed by the driver.
Innovation Solution
An electronically locking differential assembly with a lock detection mechanism that includes a biasing member and a mechanical switch, where the armature translates to change the switch's state, allowing for real-time detection of the lock state through a normally open or closed configuration, ensuring the driver is informed of the differential's locked or unlocked status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electromagnetic coil is used to actuate the locking mechanism, then the locking function can be controlled, but the lock state cannot be reliably detected in real-time
Solution Approach 1:
The patent implements a feedback mechanism by coupling the armature directly to a mechanical switch. When the armature moves to the locked position, it physically actuates the switch to change its state, providing real-time feedback about the lock state. This resolves the contradiction by ensuring that the detection system reliably reflects the actual lock state without information loss.
Solution Approach 2:
The patent introduces a mechanical switch as an intermediary between the armature and the detection system. The switch translates the physical position of the armature into an detectable signal state, serving as a mediator that converts mechanical movement into reliable state information. This intermediary ensures accurate lock state detection while maintaining system reliability.
2Stability of the object's composition
If the differential remains locked after de-energizing the electromagnetic coil, then the locking function is maintained, but unintended locking occurs that goes unnoticed by the driver
Solution Approach 1:
The mechanical switch provides continuous feedback about the actual lock state to the control system. When the differential is locked, the switch state reflects this condition, enabling the control system to detect and prevent unintended locking by comparing the expected state with the actual detected state.
Solution Approach 2:
The system uses the mechanical switch to detect lock state in advance before harmful unintended locking occurs. By monitoring the switch state, the control system can take preliminary anti-action to prevent unintended locking by de-energizing the coil or activating warning signals before the locking becomes problematic.
3Loss of information
If a lock detection mechanism is added, then real-time lock state detection is achieved, but the device complexity increases
Solution Approach 1:
The patent merges the lock detection function with the existing electromagnetic actuator by coupling the mechanical switch directly to the armature. This integration allows the detection mechanism to share the same physical components and space as the actuation mechanism, reducing overall device complexity while maintaining real-time lock state detection capability.
Solution Approach 2:
The mechanical switch is actuated automatically by the movement of the armature itself, without requiring separate actuators or complex sensing systems. The armature serves its dual purpose of both actuating the locking mechanism and triggering the detection switch, allowing the system to detect lock state through self-service rather than requiring additional independent detection components.
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
The solution provides real-time assurance to the driver about the differential's lock state, preventing unintended locking and enhancing safety by ensuring the differential returns to an unlocked state even after the electromagnetic coil is de-energized.
Implementation Method 1
an electromagnetic coil arranged to axially move the armature when energized with an electrical input signal
Implementation Method 2
a biasing member that biases the first member toward an open position indicative of an unlocked state
Data Source
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AI summary
An electronically locking differential assembly constructed in accordance to the present disclosure includes a differential casing, a first and second side gear, a lock actuation assembly and a lock detect mechanism. The first gear defines a first shaft opening configured to provide a first torque transmitting connection with a first output shaft received within the first output shaft opening. The second side gear defines a second output shaft opening configured to provide a second torque transmitting connection with a second output shaft received within the second output shaft opening. The lock actuation mechanism selectively moves between a locked state where the side gears are fixed for concurrent rotation and an unlocked state where the side gears rotate relative to each other. The lock detect mechanism detects whether the lock actuation mechanism is in the locked or unlocked state.