Spiral Leaf-Spring Vibration Actuator for Quiet High-Amplitude Motion
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Solution Overview
Problem
Conventional vibration actuators with a shaft for movable body sliding in a fixing body experience sliding noise, reducing vibration amplitude due to contact noise, and lack impact resistance.
Innovation Solution
A vibration actuator design featuring a movable body with a magnet inside a coil, supported by elastic leaf springs that prevent contact with the coil holding part, allowing for high-amplitude vibration without noise and enhanced impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shaft is provided for the movable body to slide in the fixing body, then impact resistance is improved, but sliding noise is generated reducing vibration amplitude
Solution Approach 1:
The patent replaces the mechanical sliding contact system (movable body sliding on shaft) with a magnetic field-based actuation system. The coil generates a magnetic field that interacts with the magnet on the movable body, enabling contactless actuation. This substitution eliminates mechanical friction and sliding noise while maintaining impact resistance through the magnetic coupling mechanism.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the coil and the movable body. Instead of direct mechanical contact, the magnetic field mediates the force transmission, allowing the movable body to be actuated without physical contact. This intermediary approach eliminates sliding noise while transferring the actuation force effectively.
2Reliability
If the distance between the magnet and the coil is increased to prevent contact, then coil protection is improved, but magnetic field strength decreases
Solution Approach 1:
The patent employs dynamic actuation by applying alternating current to the coil, creating a time-varying magnetic field that dynamically interacts with the magnet. This dynamic approach allows for strong magnetic coupling forces despite the increased distance, as the alternating magnetic field continuously reinforces the interaction between the coil and magnet during vibration cycles.
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 enables high-output vibration transmission with reduced noise and improved impact resistance, ensuring effective sensory feedback in electronic devices.
Implementation Method 1
a movable body 20 including a magnet 30... configured to vibrate with respect to the fixing body by cooperation of the magnet and the coil to which power is fed
Implementation Method 2
the elastic support part includes at least two or more leaf springs provided across the coil holding part and the movable body... the leaf springs support the movable body such that the movable body is movable in the vibration direction without making contact with the coil holding part
Data Source
AI summary
A vibration actuator includes: a movable body including: a disk-shaped magnet; a pair of disk-shaped cores fixed on front and rear surfaces of the disk-shaped magnet and each having an opening at a center thereof; a pair of leaf springs having a substantially circular shape; and a pair of spring stopper weight parts each having one end positioned by joining the opening to be joined with one of the disk-shaped cores and having another end connected to a central part of one of the leaf springs; and a fixing body including an annular coil and configured to support and accommodate therein the movable body such that the disk-shaped magnet, the disk-shaped cores and the spring stopper weight parts are capable of vibrating in an axial direction inside the annular coil.