Magnetic Control System for Overrunning Coupling Position Sensing
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Solution Overview
Problem
Current clutch-position sensing systems in automatic transmissions face accuracy issues due to gaps between sensors and the object being sensed, leading to potential mechanical wear and inefficiencies, particularly in addressing tip-in clunk and shift harshness in powershift transmissions.
Innovation Solution
A magnetic control system for overrunning coupling assemblies, incorporating a ferromagnetic element movable between coupling and uncoupling positions, an electromagnetic source with an excitation coil, and a magnetic field sensor to generate a variable magnetic field and provide accurate position feedback, enhancing clutch control and reducing parasitic losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic field sensor is used to sense clutch position, then sensing accuracy is improved and mechanical wear is reduced, but the system complexity increases due to the electromagnetic source and control circuitry
Solution Approach 1:
The patent replaces mechanical contact-based position sensing with a magnetic field sensing system. The magnetic field sensor detects the position of the ferromagnetic element without physical contact, eliminating mechanical wear while providing accurate position feedback for clutch control.
Solution Approach 2:
The patent introduces a ferromagnetic element as an intermediary between the electromagnetic source and the magnetic field sensor. This element modulates the magnetic field based on its position, enabling the sensor to detect clutch engagement state without direct mechanical contact between sensing components.
2Manufacturing precision
If a magnetic field sensor and electromagnetic source are integrated, then clutch control precision is improved, but parasitic losses increase due to the additional electromagnetic components
Solution Approach 1:
The patent uses an excitation coil to dynamically change the magnetic field parameters, attracting the ferromagnetic element to precise positions. This electromagnetic control provides accurate clutch engagement without the parasitic losses associated with traditional mechanical spring-loaded sensing systems.
3Device complexity
If traditional mechanical clutch-position sensing is used, then the system structure remains simple, but mechanical wear occurs and sensing accuracy deteriorates
Solution Approach 1:
The patent eliminates mechanical contact in the sensing system by using magnetic field interaction. The magnetic field sensor and ferromagnetic element provide contactless position detection, significantly improving reliability by removing wear-prone mechanical components while maintaining relatively simple system structure.
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 magnetic control system improves clutch-position sensing accuracy and reduces mechanical wear, enabling smoother gear shifts and eliminating tip-in clunk and shift harshness in powershift transmissions by providing precise control over the clutch engagement.
Implementation Method 1
An electromagnetic source including at least one excitation coil is provided
Implementation Method 2
A magnetic field sensor is provided which is stationary with respect to the ferromagnetic element and which senses magnetic flux to produce an output signal which is based on the position of the ferromagnetic element
Data Source
AI summary
A magnetic system for controlling the operating mode of an overrunning coupling assembly is provided. The system includes a ferromagnetic or magnetic element received within a pocket in an uncoupling position and is movable outwardly from the pocket to a coupling position. The element controls the operating mode of the coupling assembly. An armature is connected to the element to move the element between the coupling and uncoupling positions. A magnetic field sensor is disposed adjacent and stationary with respect to the element for sensing magnetic flux to produce an output signal which is based on the position of the element. A variable magnetic field is generated in response to movement of the element between the coupling and uncoupling positions.