Electrodynamic Boring Bar Layout for Low-Frequency Vibration Damping
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Solution Overview
Problem
Existing boring bars face challenges in effectively counteracting low-frequency vibrations, particularly in constrained environments, with piezoelectric actuators generating limited displacements and electromagnetic actuators requiring complex control and high energy consumption.
Innovation Solution
A boring bar equipped with dual electrodynamic actuators, each oriented perpendicularly to the longitudinal axis, utilizing coil windings and permanent magnets with springs for efficient vibration damping, allowing for high force generation and linear control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If piezoelectric actuators are used to counteract vibrations, then the device can be compact and easy to control, but the actuator generates limited displacements and cannot effectively counteract low-frequency vibrations
Solution Approach 1:
The patent replaces piezoelectric actuators (mechanical/ceramic system with limited displacement) with electrodynamic actuators consisting of coil windings and permanent magnets. This substitution enables generation of strong electromagnetic forces capable of counteracting low-frequency vibrations while maintaining compact dimensions suitable for constrained boring bar environments.
Solution Approach 2:
The patent changes the actuation mechanism from piezoelectric deformation (maximum 0.1% deformation rate) to electromagnetic force generation. By utilizing the electrodynamic effect with coil windings and permanent magnets, the system achieves much larger displacements and forces, particularly effective at low frequencies where piezoelectric actuators fail.
2Force
If electromagnetic actuators are used to generate large forces for low-frequency vibration counteraction, then the force capability is improved, but the control complexity increases and energy consumption rises
Solution Approach 1:
The patent divides the vibration counteraction task into two independent electrodynamic actuators, each oriented perpendicular to the longitudinal axis (one in radial direction, one in tangential direction). Each actuator handles vibrations in its specific direction independently, simplifying the control algorithm compared to managing a single complex multi-directional actuator.
Solution Approach 2:
The patent employs sensors (accelerometers) to detect vibrations and uses a processor to generate periodic control signals for the electrodynamic actuators. The actuators receive periodic voltage signals that correspond to the detected vibration frequencies, enabling effective counteraction through synchronized periodic action rather than complex continuous control.
3Volume of moving object
If the boring bar operates in constrained internal volume, then the device fits the application requirements, but there is insufficient space for large piezoelectric actuators
Solution Approach 1:
The patent replaces space-intensive piezoelectric actuators with electrodynamic actuators that generate equivalent or superior forces within a more compact volume. The coil windings and permanent magnets can be arranged efficiently within the constrained internal volume of the boring bar, achieving the required force generation without exceeding spatial constraints.
4Force
If larger piezoelectric actuators are installed outside the boring bar, then the displacement capability is improved, but the device complexity and installation requirements increase
Solution Approach 1:
The patent merges the actuator system with the boring bar structure itself. The electrodynamic actuators are integrated within the internal recess of the boring bar, with coil windings and permanent magnets arranged to utilize the existing structural space. This merging eliminates the need for separate external actuator installations and simplifies the overall device architecture.
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 effective damping of vibrations in both radial and tangential directions, suitable for constrained spaces, with improved force generation and control efficiency, reducing machining defects.
Implementation Method 1
an actuator comprises coil windings (101, 102) surrounding a moving mass (110) provided with at least one permanent magnet (111)
Implementation Method 2
at least one spring (120, 121) mounted on the moving mass (110)
Data Source
AI summary
A boring bar with electrodynamic actuators is for counteracting vibrations and machine tool provided with such a bar. The boring bar includes a wall, an internal recess and a longitudinal axis. The boring bar has a first electrodynamic actuator with coil windings associated with a moving mass and a spring assembly that are arranged to define a first actuation direction perpendicular to the longitudinal axis of the boring bar. A second electrodynamic actuator has coil windings associated with a moving mass and a spring assembly that are arranged to define a second actuation direction perpendicular to both the first actuation direction and the longitudinal axis of the boring bar. The actuators allow counteraction of the vibrations in the directions perpendicular to the longitudinal axis of the bar. The longitudinal axis also defines the boring direction.