Leaf-Spring Vibration Actuator With Coil Contact Protection

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Solution Overview

Problem

Conventional vibration actuators experience noise due to sliding contact during operation, which reduces vibration amplitude and impact resistance, necessitating a solution that maintains high output and impact resistance while minimizing noise.

Innovation Solution

A vibration actuator design featuring a movable body supported by elastic support parts and a coil holding part that prevents contact between the movable body and coil, allowing for vibration without noise, utilizing a disk-shaped magnet, annular yokes, and leaf springs to facilitate movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the movable body is allowed to move freely during vibration, then vibration amplitude and output are improved, but sliding contact noise occurs and reliability deteriorates

Engineering Contradiction:

Improvevibration outputVSAvoidnoise-free operation

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent introduces a shaft as an intermediary component between the movable body and the fixed body. The shaft enables the movable body to move in the vibration direction while being guided and constrained, preventing sliding contact noise and improving reliability during vibration operation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct sliding contact between the movable body and fixed body with a mechanical guidance system using the shaft. This substitution eliminates the harmful sliding friction and noise while maintaining the necessary vibration movement

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If the yoke is positioned closer to the coil for stronger magnetic field, then vibration output is improved, but the yoke may collide with the coil during external shock, causing damage

Engineering Contradiction:

Improvevibration outputVSAvoidshock resistance

Core Design Contradiction:

PowerVSStrength

Solution Approach 1:

The patent positions the yoke at a predetermined distance from the coil, creating a protective gap before external shock can cause collision. This preemptive spacing cushions against potential damage while maintaining sufficient magnetic field strength for vibration output

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the yoke is positioned farther from the coil to prevent collision, then shock resistance is improved, but magnetic field strength decreases, reducing vibration output

Engineering Contradiction:

Improveshock resistanceVSAvoidvibration output

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent optimizes the distance parameter between the yoke and coil to achieve a balance point. By carefully controlling this dimensional parameter, the design maintains sufficient magnetic field strength for adequate vibration output while ensuring the yoke is far enough to prevent collision during external shock

Inventive Principle:

Principle #35Parameter changes

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 with high output and impact resistance, ensuring effective transmission of vibrations without noise, enhancing user experience.

Implementation Method 1

a movable body (20) including a disk-shaped magnet (30)... configured to vibrate with respect to the fixing body (50) by cooperation of the disk-shaped magnet (30) and the coil (61, 62) to which power is fed

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a pair of elastic support parts (81, 82) configured to movably support the movable body (20) with respect to the fixing body (50)... each elastic support part includes a respective leaf spring

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentEP3846326B1Vibration actuator and electronic equipment

Publication Date: 2025.10.22 MINEBEAMITSUMI INC

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AI summary

This vibration actuator has: a stationary body having a coil; a movable body having a magnet disposed radially inside the coil; and an elastic support part for supporting the movable body so that the movable body can move relative to the stationary body, and the coil to which electric power is supplied and the magnet cooperate to vibrate the movable body relative to the stationary body. The stationary body is disposed so as to surround the movable body and has a coil holding part for holding the coil. The coil holding part has, on the inner diameter side of the coil, a coil protection wall part which prevents the contact between the magnet and the coil. The elastic support part has at least two or more plate springs bridged between the coil holding part and the movable body so as to sandwich the movable body in a vibration direction. In order that the movable body does not come into contact with the coil holding part when not vibrating and when vibrating, the plate springs support the movable body so that the movable body is movable in the vibration direction.