Electromagnetic Locking Differential With Engagement Status Sensing
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Solution Overview
Problem
Conventional open differentials fail to provide adequate traction on split-mu surfaces, leading to issues like tire scuffing and inability to climb hills, whereas locked differentials offer improved traction but lack electronic control and real-time status indication.
Innovation Solution
An electronically controlled locking differential assembly with a lock collar, coil, armature, and sensor system that allows for automatic or manual switching between unlocked and locked states, providing enhanced torque and real-time engagement status feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a locked differential is used, then traction and torque transmission are improved, but the device complexity increases due to additional locking mechanisms
Solution Approach 1:
The patent replaces traditional mechanical locking mechanisms with an electromagnetic actuation system. A coil generates a magnetic field that magnetically actuates an armature, which in turn actuates the lock collar. This substitution of mechanical systems with electromagnetic systems reduces mechanical complexity while maintaining the locking function, directly resolving the contradiction between improved traction and reduced device complexity.
Solution Approach 2:
The patent introduces an armature as an intermediary component between the coil and the lock collar. The armature translates the magnetic force from the coil into mechanical movement of the lock collar. This intermediary mechanism allows for smooth, controlled engagement and disengagement of the locking mechanism, reducing the complexity of direct mechanical actuation while ensuring reliable traction control.
2Ease of operation
If an open differential is used, then ease of operation in turns is improved, but traction on slippery surfaces deteriorates
Solution Approach 1:
The patent creates a dynamic differential system that can switch between unlocked and locked states based on operating conditions. The electromagnetic actuation system allows the differential to be unlocked during normal operation for easy turning, and locked when traction is needed on slippery surfaces. This dynamic adaptability resolves the contradiction by providing both ease of operation and reliable traction as needed.
Solution Approach 2:
The patent changes the operational state parameter of the differential from fixed (either locked or unlocked) to variable. By using electromagnetic actuation, the system can dynamically adjust the locking state based on traction requirements. This parameter change allows the differential to optimize between ease of operation and traction reliability depending on the driving conditions.
3Loss of information
If a sensor system is added to provide real-time status indication, then information feedback is improved, but device complexity increases
Solution Approach 1:
The patent incorporates a sensor system that provides real-time feedback on the engagement status of the lock collar. This feedback mechanism allows the system to monitor and report the differential's operational state, improving information availability. The sensor integrates with the existing electromagnetic actuation system, providing feedback functionality while leveraging existing system components to minimize additional complexity.
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
Enables higher torque transmission and improved traction on various surfaces, including split-mu conditions, while offering detailed operational status feedback to the user, enhancing vehicle performance and user experience.
Implementation Method 1
An armature is selectably magnetically actuatable by the coil
Data Source
AI summary
A locking differential assembly includes a differential case defining an axis of rotation. A lock collar is selectably engageable with a first side gear to selectably prevent the first side gear and a second side gear from rotating relative to the differential case. A coil disposed at an end of the differential case. An armature selectably magnetically actuatable by the coil. An armature position indicator arm rigidly attached to the armature for simultaneous movement with the armature. At least two relay pin assemblies are each connected to the lock collar and connected to the armature to space the lock collar a predetermined distance from the armature for translation parallel to the axis of rotation. A sensor connected to the differential case to detect a proximity of the armature position indicator arm to the sensor and to output an electrically detectable signal indicative of an engagement status of the lock collar.