Non-magnetic Ring for Hall Sensor Position Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hall sensors in automatic transmission shift elements are prone to signal manipulation by metallic particles, leading to inaccurate detection of the axial position of axially movable dogs, which can disrupt the operation of dog-clutch shift elements.
Innovation Solution
A ring-shaped component made of non-magnetic material is placed around the axially movable shift element half to protect the encoder contour from metallic particles, ensuring the magnetic field for travel detection remains unshielded and allowing hydraulic oil to flow around it, thus preventing signal disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall sensor is used to detect the axial position of the axially movable dog, then the travel detection precision is improved, but the sensor signal is manipulated or falsified by metallic particles
Solution Approach 1:
A non-magnetic protective element is introduced as an intermediary component between the Hall sensor and the encoder contour on the axially movable dog. This protective element blocks metallic particles from reaching the encoder contour while allowing the magnetic field to pass through, thus protecting the sensor signal from manipulation without affecting the detection precision
Solution Approach 2:
The protective element is designed to be transparent to the magnetic field used by the Hall sensor, converting the potential harm of blocking particles into a beneficial filtering function. The non-magnetic material allows the magnetic field to pass through while blocking metallic particles, thus protecting the sensor without interfering with the measurement
2Reliability
If the encoder contour is protected against metallic particles, then the sensor signal reliability is improved, but the hydraulic duct may be closed or volume flow limited
Solution Approach 1:
The protective element is designed with local quality differentiation: it provides complete protection against metallic particles in the region of the encoder contour while maintaining hydraulic flow capability in other regions. The protective element's geometry is optimized to block particles locally without impeding the overall hydraulic flow through the shift element
Solution Approach 2:
The protective element is designed as a segmented or perforated structure that divides the hydraulic flow path into multiple channels. This segmentation allows metallic particles to be blocked while hydraulic oil can flow through the gaps, thus protecting the sensor without limiting the volume flow
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 design effectively prevents metallic particles from interfering with the Hall sensor signal, ensuring accurate detection of the axial position of the axially movable dog without limiting hydraulic flow or closing the hydraulic duct, thereby maintaining the efficiency and reliability of the dog-clutch shift element.
Implementation Method 1
A Hall sensor arranged in the bearing carrier of the dog-clutch shift element is preferably used for detecting the travel of the axially movable dog
Implementation Method 2
a ring-shaped component composed of a non-magnetic material which is transparent to the Hall sensor
Data Source
AI summary
A shift element (4) for an automatic transmission having a hydraulically actuable piston; at least one hydraulic duct (10); an axially movable first shift element half (3, 7) operatively connected to the piston; a second shift element half (8); a bearing carrier (9); a ring-shaped component (1); and a Hall sensor (6) in the bearing carrier (9). The first shift element half (3) has a notch-like encoder contour (5) for the Hall sensor (6). The ring-shaped component (1) is composed of a non-magnetic material transparent to the Hall sensor (6). The ring-shaped component (1) is designed and arranged on the outer diameter of the first shift element half (3), such that an air gap between the notch-like encoder contour (5) and the Hall sensor (6) is filled by the ring-shaped component (1), and hydraulic oil flows in the remaining region along the circumference of the first shift element half (3).