Non-Contact Speed Detection Using Lorentz Force and Motor Current
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Solution Overview
Problem
Existing speed detection technologies face challenges in detecting the speed of moving bodies without a magnet and are prone to breakage due to vibrations when used in contact mode.
Innovation Solution
A non-contact speed detecting device that uses a rotating body with a permanent magnet, driven by a Lorentz force, and a motor to control its speed, detecting the electric current to estimate the moving body's speed, with optional correlation and magnetic coupling degree estimation units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a magnet is attached to the moving body for non-contact speed detection, then speed detection capability is improved, but the device cannot detect speed of moving bodies without magnets
Solution Approach 1:
The patent replaces the traditional electromagnetic induction sensor that requires a magnet with a sensor that detects speed through mechanical contactless means, likely using optical or capacitive fields, thereby eliminating the requirement for magnet attachment while maintaining non-contact detection capability
Solution Approach 2:
The sensor is designed to detect the speed of various moving bodies regardless of whether they have magnets attached, making the device universal and adaptable to different applications without requiring modification or attachment of additional components
2Device complexity
If a contact type sensor is used for speed detection, then the device structure is simplified, but the sensor is susceptible to breakage due to vibrations
Solution Approach 1:
The patent replaces contact-type mechanical sensors with non-contact sensors that use electromagnetic or optical fields to detect speed, eliminating physical contact and thereby preventing wear and breakage from vibrations while maintaining structural simplicity
3Reliability
If a non-contact electromagnetic induction sensor is used, then reliability is improved by avoiding contact, but a magnet must be attached to the moving body
Solution Approach 1:
The patent substitutes the electromagnetic induction sensing method with an alternative non-contact sensing method that does not require magnetic fields, thereby maintaining the reliability benefits of non-contact operation while eliminating the complexity of magnet attachment
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
Accurately detects the moving or rotating speed of a moving body in a non-contact manner, enhancing reliability and durability by avoiding direct contact and magnet attachment requirements.
Implementation Method 1
the permanent magnet being configured to be driven to rotate about a predetermined rotation axis by a Lorentz force produced in accordance with a rotating or moving direction of the moving body
Implementation Method 2
a motor configured to apply a further rotational drive force to the rotating body
Data Source
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AI summary
One object is to accurately detect a moving or rotating speed of a moving body in a non-contact manner. A speed detecting device 1 includes: a rotating body 2 including a permanent magnet, the rotating body 2 being spaced above a principal surface of a moving body, the moving body 8 being a conductor configured to rotate or move, the permanent magnet being configured to rotate about a predetermined rotation axis by a Lorentz force produced in accordance with a rotating or moving direction of the moving body; a motor 3 for applying a rotational drive force to the rotating body; a rotation control unit 4 for controlling the rotational drive force applied by the motor to the rotating body to vary a rotating speed of the rotating body; a current detecting unit 5 for detecting a value of electric current flowing through the motor during an operation to rotate the rotating body at a desired rotating speed, the rotating body receiving a rotational drive force of the Lorentz force; and a moving speed estimating unit 6 for estimating a moving or rotating speed of the moving body based on the value of the electric current detected by the current detecting unit.