Linear Magnetic Encoder with Flexible Track and Rotating Sensor Magnet
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Solution Overview
Problem
Existing linear magnetic encoders struggle with accuracy and durability in harsh environments, particularly due to inflexible magnet-carrying tracks that can deform or detach under stress, leading to positional errors and system failure, and they are limited to rotary applications.
Innovation Solution
A linear magnetic encoder with a freely rotatable bipolar cylindrical sensor magnet that interacts with spaced apart elongate position magnets, allowing for accurate position determination while maintaining magnetic field coupling during linear movement, and a flexible track construction that can deform without detaching, enabling robust operation under vibrations and shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid magnet-carrying track is used in linear magnetic encoders, then manufacturing precision can be maintained, but the track deforms or detaches under stress from vibrations and shocks, leading to system failure
Solution Approach 1:
The patent employs a flexible magnet-carrying track that can deform under stress without detaching. This flexible track is designed to accommodate vibrations and shocks while maintaining magnetic field coupling between the track-mounted magnets and the sensor, thereby improving reliability without sacrificing manufacturing precision
Solution Approach 2:
The patent changes the physical state of the track from rigid to flexible, allowing it to dynamically adapt its shape under various stress conditions. This parameter change enables the track to absorb mechanical shocks and vibrations while maintaining functional integrity and positional accuracy
2Measurement precision
If optical encoders are used for high accuracy position sensing, then measurement precision is improved, but the system becomes sensitive to dust, oil, dirt, high temperature, shock and vibration
Solution Approach 1:
The patent replaces the optical sensing system with a magnetic sensing system. Instead of using light sources, optical sensors, and coded disks that are sensitive to environmental factors, the system uses magnetic fields and magnetic sensors that are inherently more robust against dust, oil, dirt, high temperature, shock, and vibration while maintaining high measurement precision
3Reliability
If mechanical encoders are used for position detection, then contact-type sensing is achieved, but the application range is limited and wear occurs due to direct contact
Solution Approach 1:
The patent replaces mechanical contact-type sensing with non-contact magnetic field sensing. This substitution eliminates wear from direct contact while expanding application versatility to include environments where mechanical contact would be problematic, such as high-temperature, high-vibration, or contamination-prone settings
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 high positional accuracy and durability, allowing the linear magnetic encoder to maintain precise position measurement even under conditions of pitch, roll, and yaw variations, and bending, while preventing track detachment and ensuring continuous operation.
Implementation Method 1
a magnetic field sensor configured to detect changes in a flux of a magnetic field of the sensor magnet
Implementation Method 2
interaction and coupling of the magnetic fields of the sensor magnet and each adjacent pair of position magnets drives the sensor magnet into rotation during linear movement
Data Source
AI summary
A linear magnetic encoder or position sensor having read head with a freely rotatable generally cylindrical bipolar magnet onboard having an axially extending axis of rotation through the center of the sensor magnet that is generally parallel with respect to the longitudinal extent of a plurality of pairs of elongate bar position magnets arranged with alternating opposite magnetic poles facing toward to the read head and sensor magnet that are generally aligned and spaced apart a common fixed distance along a track along which the read head and sensor magnet travels. Magnetic fields extending between the opposite magnetic poles of each pair of position magnets interact with and preferably magnetically couple with a magnetic field of the sensor magnet inducing a force, preferably a torque, therein driving the sensor magnet into rotation as the head and sensor magnet travel along the position magnet pair. One axial end of the sensor magnet is disposed adjacent and faces toward a sensor region of an onboard magnetic sensor configured to detect an angle of rotation and number of rotations of the sensor magnet used to determine a linear position along the track.