Soft Magnetic Rotor Vibration Control With Coil Switching
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Solution Overview
Problem
Conventional vibration control devices with magnets fixed to an output shaft and coils on the outer circumference face increased voltage issues as rotation speed rises, leading to complex and costly circuit requirements.
Innovation Solution
A vibration control device with a soft magnetic rotor and multiple pairs of coils, where the rotor's pole parts protrude in radially opposite directions, and a switching circuit that disconnects coils from the charger-discharger when rotation speed is outside an effective range, reducing torque ripple and simplifying the configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnets are fixed to the output shaft and coils are provided on the outer circumference of the magnet, then vibration control effect is achieved, but voltage increases with rotation speed requiring complex and costly high-voltage durable circuits
Solution Approach 1:
The patent extracts the magnet from the rotating output shaft and places it on the stationary rotor, while extracting the coil from the stationary position and placing it on the rotating rotor. This separation removes the source of high-voltage generation (relative motion between magnet and coil) while preserving the vibration control function through the rotor's interaction with the stator.
Solution Approach 2:
The patent inverts the conventional arrangement by making the rotor a soft magnetic body instead of a permanent magnet, and placing coils on the stator instead of on the outer circumference of a rotating magnet. This inversion eliminates electromotive force generation during rotation while maintaining the ability to generate torque for vibration control.
2Reliability
If magnets are fixed to the output shaft and coils are provided on the outer circumference of the magnet, then vibration control effect is achieved, but the configuration becomes complex and costly
Solution Approach 1:
The patent extracts the magnet from the rotating output shaft and places it on the stationary rotor, while extracting the coil from the stationary position and placing it on the rotating rotor. This separation removes the source of high-voltage generation (relative motion between magnet and coil) while preserving the vibration control function through the rotor's interaction with the stator.
Solution Approach 2:
The patent inverts the conventional arrangement by making the rotor a soft magnetic body instead of a permanent magnet, and placing coils on the stator instead of on the outer circumference of a rotating magnet. This inversion eliminates electromotive force generation during rotation while maintaining the ability to generate torque for vibration control.
3Device complexity
If the rotor is made of soft magnetic body, then electromotive force generation is hampered and circuit durability requirements are lowered, but torque generation capability must be maintained
Solution Approach 1:
The patent introduces a switching circuit as an intermediary between the coil and the power source, controlling when the coil is energized. This allows torque to be generated only when needed (when the rotor is in a specific angular position relative to the stator), maintaining force generation capability while preventing continuous electromotive force generation that would require high-voltage durable circuits.
Solution Approach 2:
The patent employs periodic action by controlling the switching circuit to energize the coil only during specific periods when the rotor is in the appropriate angular position. This periodic energization generates torque when needed while avoiding continuous operation that would generate harmful electromotive force, thereby simplifying circuit 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 effectively reduces torque ripple while lowering the durability requirements of the circuit, allowing for a simpler and more reliable vibration control device configuration.
Implementation Method 1
a coil provided on the stator; a switching circuit that switches connection of the coil to a charger-discharger
Implementation Method 2
The rotor is formed of a soft magnetic body. This hampers the rotor from generating electromotive force in the coils even when the rotor simply rotates
Data Source
Figure 1~2
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AI summary
A vibration control device includes: a rotor formed of a soft magnetic body and fixed to an output shaft of a rotation driver or to a shaft that rotates in conjunction with the output shaft, the rotor being configured to rotate in response to rotation of the output shaft; a stator provided in a radial circumference of a rotation axis of the rotor; coils fixed to the stator and provided in a pair with the rotation axis therebetween; a charger-discharger provided in such a manner as to be connectable to the coils; a switching circuit provided capable of switching between connecting and disconnecting the coils and the charger-discharger; a first detector configured to detect a rotation angle of the rotor; and a control circuit configured to control operation of the switching circuit in accordance with the rotation angle of the rotor.