Locking Differential Armature Position Sensing by Inductance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electronically actuated locking differentials face challenges in electronically sensing the locked state due to non-contacting sensors on rotating armatures, leading to increased costs and wear concerns.
Innovation Solution
A position detection device with a secondary coil is used to determine the position of the armature relative to the stator by measuring changes in inductance, allowing for accurate detection of the locked or unlocked state without the need for a non-contacting sensor on the rotating armature, and utilizing a retaining clip made of low magnetic permeable material to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a non-contacting sensor is attached to the rotating armature to detect the locked state, then the detection capability is improved, but the cost increases and wear and durability concerns arise
Solution Approach 1:
The patent introduces a magnetic field as an intermediary between the armature and the stator. The armature's magnetic field changes as it rotates, and these changes are detected by the stator without direct contact. This intermediary magnetic field allows for contactless sensing of the armature's position and state, resolving the contradiction between detection capability and wear/durability concerns
Solution Approach 2:
The patent replaces the mechanical contact-based sensing system with an electromagnetic sensing system. Instead of using physical sensors that contact the rotating armature, the system uses magnetic field detection through the stator to sense the armature's position and locked state, eliminating mechanical wear and reducing system complexity
2Measurement precision
If a sensor is attached to the rotating armature to detect position, then the position detection is enabled, but wear and durability become concerns
Solution Approach 1:
The magnetic field serves as an intermediary that transmits position information from the rotating armature to the stationary stator without physical contact. The stator detects changes in the magnetic field as the armature rotates, enabling continuous position detection while eliminating wear and durability issues associated with contact-based sensors
Solution Approach 2:
The patent replaces mechanical contact-based position sensing with electromagnetic field-based sensing. The stator detects the armature's position through changes in the magnetic field pattern, eliminating the need for physical sensors on the rotating armature and thereby improving reliability by removing wear-prone 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
This solution enables reliable and cost-effective detection of the locking state, reducing wear and friction, and providing real-time status to the driver, while minimizing electromagnetic interference and improving durability.
Implementation Method 1
The secondary coil is configured to determine a change in inductance based on movement of the armature. The change in inductance is indicative of a change in position of the armature relative to the stator.
Implementation Method 2
The stator has a primary coil that defines a primary coil axis. The armature moves relative to the stator between engaged and disengaged positions corresponding to the locking differential being in a locked and unlocked state.
Data Source
AI summary
A position detection device configured for use with a locking differential is configured to determine a position of an armature in relation to a stator. The stator has a primary coil. The armature moves relative to the stator between engaged and disengaged positions corresponding to the locking differential being in a locked and unlocked state. The position detection device includes a secondary coil disposed proximate to the primary coil. The secondary coil is configured to determine a change in inductance based on movement of the armature. The change in inductance is indicative of a change in position of the armature relative to the stator.