Actuator Position Sensor Shielding from Coil Interference
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Solution Overview
Problem
Existing position sensors for locking gearsets in motor vehicles face issues with wear, mounting problems, and accuracy due to external magnetic fields and runout of moving parts, particularly with magnetic proximity sensors.
Innovation Solution
An actuator assembly with an electromagnetic coil, armature, pressure plate, and a sensor assembly that includes a follower with a magnet and a sensor housing, where the sensor is oriented to avoid interference from the magnetic flux path, allowing for accurate sensing of the linear position of the locking gearset.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic proximity sensors are used to sense the position of the actuator assembly, then the sensing capability is provided, but the accuracy is reduced due to interfering fields from the electromagnetic actuator coil
Solution Approach 1:
The patent extracts the sensor assembly from the direct vicinity of the electromagnetic coil by positioning it on the outer radial end of the actuator housing, away from the coil assembly. This spatial separation removes the sensor from the harmful electromagnetic field zone, allowing accurate position sensing without interference from the actuator coil's magnetic flux.
Solution Approach 2:
The patent introduces a non-magnetic spacer or housing structure as an intermediary between the electromagnetic coil and the sensor assembly. This intermediary element shields the sensor from the electromagnetic field while allowing the sensor to detect the position of the actuator assembly through mechanical coupling or optical means that are not affected by the magnetic field.
2Measurement precision
If magnetic proximity sensors are used to sense the position of the actuator assembly, then the sensing capability is provided, but the accuracy is reduced due to runout of moving parts
Solution Approach 1:
The patent replaces direct mechanical contact-based position sensing with a non-contact sensing method. The sensor assembly uses optical or capacitive sensing to detect the position of the actuator assembly without physical contact, eliminating the errors caused by mechanical runout and wear associated with traditional mechanical sensors.
Solution Approach 2:
The sensor assembly is designed to sense the position of multiple components (armature, pressure plate, actuator assembly) simultaneously through a single multi-functional sensing mechanism, reducing the impact of runout by using a reference frame that is stable relative to the actuator housing rather than relying on multiple separate mechanical contact points.
3Measurement precision
If mechanical positional sensors are used to sense the position of the actuator assembly, then the position information is provided, but wear and mounting issues occur
Solution Approach 1:
The patent replaces mechanical positional sensors with a non-contact sensor assembly that uses optical, capacitive, or inductive sensing principles. This substitution eliminates wear between moving parts and reduces mounting complexity, as the sensor can be mounted on the stationary actuator housing and sense the position of moving components through their electromagnetic or optical fields without physical contact.
Solution Approach 2:
The sensor assembly is designed to be self-aligning and requires minimal calibration or adjustment during mounting. The sensing mechanism automatically adapts to the position of the actuator assembly components, reducing the need for precise mounting tolerances and field adjustments, thereby improving reliability and reducing maintenance requirements.
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 improved accuracy and reduced sensitivity to external magnetic fields and runout, enabling reliable detection of the locking gearset's position, enhancing the overall performance of the actuator assembly.
Implementation Method 1
the actuator converts electrical current from the controller into mechanical force. As is known in the art, the actuator converts electrical current into mechanical force. For example, the flow of electrical current creates a magnetic field that moves a pressure plate of the actuator
Implementation Method 2
The sensor assembly includes a follower having a magnet disposed therein and a recess for receiving the rim of the pressure plate, a sensor housing having a slot for receiving the follower, and a sensor fixed within the sensor housing between the sensor housing and the follower
Data Source
AI summary
An apparatus for sensing the position of an actuator assembly having electromagnetic coil, a pressure plate with a rim on one end thereof, and a sensor assembly attached to the actuator assembly. The sensor assembly includes a follower having a magnet disposed therein and a recess for receiving the rim of the pressure plate, a sensor housing having a slot for receiving the follower, and a sensor fixed within the sensor housing between the sensor housing and the follower.