Vibration Actuator Coil-Yoke Layout for Stable Miniaturization
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Solution Overview
Problem
There is a need for a vibration actuator that can be miniaturized while maintaining high output, as products become smaller, and must prevent mass imbalance and unstable vibration by avoiding collisions between the yoke and the frame.
Innovation Solution
A vibration actuator design featuring a movable body with a magnet and yokes, supported by elastic parts, and a coil assembly within a cylindrical frame, where the coil is positioned to prevent contact with the yoke, allowing for compact size and stable vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the vibration actuator is miniaturized to fit smaller electronic devices, then the device size is reduced, but the risk of yoke-coil collision increases and vibration output may deteriorate
Solution Approach 1:
The patent introduces a coil holder as an intermediary component between the coil and the yoke. This coil holder includes a holding portion that secures the coil and a protruding portion that extends toward the yoke, creating a physical barrier that prevents direct contact between the coil and yoke during vibration operations, thereby eliminating collision risks in miniaturized designs
Solution Approach 2:
The coil holder is pre-positioned and fixed to the frame before the coil is installed. The protruding portion of the coil holder is designed in advance to maintain a predetermined distance from the yoke, establishing collision prevention measures before the vibration actuator begins operation
2Reliability
If the distance between the yoke and coil is increased to prevent collision, then collision risk is reduced, but the vibration output and efficiency deteriorate
Solution Approach 1:
The coil holder is designed with a flexible or adjustable structure that allows optimal positioning of the coil relative to the yoke. The protruding portion can be adjusted to achieve the ideal gap distance that maximizes electromagnetic coupling while preventing contact, enabling the system to maintain high vibration output without collision risk
Solution Approach 2:
The patent optimizes the dimensional parameters of the coil holder, including the length and position of the protruding portion, to precisely control the gap between the coil and yoke. By carefully selecting these parameters, the design achieves the optimal balance between collision prevention and maintaining strong electromagnetic interaction for high vibration output
3Power
If the coil is positioned closer to the yoke to improve vibration efficiency, then power output increases, but the risk of mass imbalance and unstable vibration increases
Solution Approach 1:
The coil holder serves as a stable intermediary structure that rigidly positions the coil at an optimal distance from the yoke. This stable positioning prevents mass imbalance during vibration operations while maintaining efficient electromagnetic coupling, ensuring both high power output and vibration stability
Solution Approach 2:
The coil holder is designed with differentiated local structures: the holding portion securely anchors the coil, while the protruding portion provides precise positioning relative to the yoke. This localized functional differentiation ensures stable coil positioning that maintains vibration efficiency without compromising stability
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 design achieves suitable vibration output while downsizing, ensuring stable and high-power vibration without mass imbalance, suitable for electronic devices like game controllers and smartphones.
Implementation Method 1
a coil that is attached on an inner peripheral surface of the yoke and wound along the inner peripheral surface of the yoke; and a movable element that is enclosed by the coil, being supported along a vibration axis of the case oscillatably, and has a magnet
Implementation Method 2
an elastic support portion movably supporting the movable body with respect to the fixing body, the movable body vibrating with respect to the fixing body in a vibration direction by means of cooperation between the coil supplied with power and the magnet
Data Source
Figure 1
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AI summary
A fixing body (40) configured to house a movable body (20) including a magnet (21), and including a coil (61, 62) surrounding an outer periphery of the magnet (21) and an outer yoke (50) surrounding an outer periphery of the coil (61, 62), the fixing body (40) being configured to support the movable body (20) so as to allow the movable body (20) to vibrate back and forth in a vibration direction orthogonal to a radial direction, wherein the outer yoke (50) includes a plurality of openings (53, 55) dispersed in a circumferential direction and provided at the same position in the vibration direction to keep a balance of a magnetic path configured together with the magnet (21) and the coil (61, 62) in the circumferential direction.