Leaf-Spring Vibration Device for Quiet 10–200 Hz Haptics

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Solution Overview

Problem

Existing vibration devices for haptic applications have a larger number of components and lower vibration intensity compared to horns, and they require different vibration frequencies, making it difficult to integrate horn technology into vibration devices without generating sound.

Innovation Solution

A vibration device design that shares components with horns, using a magnetic housing, coil, stator core, and moving core, with a leaf spring member to achieve a natural frequency of 10-200 Hz, and a control system to switch energization and de-energization, allowing for quiet operation and effective vibration transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If horn technology is applied to vibration devices, then manufacturing efficiency and component sharing are improved, but sound generation occurs which is unwanted in haptic applications

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidsound generation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the resonator member from the horn structure and replaces it with a damping member that absorbs vibration energy. This removes the sound-generating function while retaining the housing, coil, stator core, and moving core components, enabling manufacturing efficiency without unwanted sound output.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful sound generation into beneficial vibration damping by using a damping member that absorbs the vibrational energy. The same structural components that would produce sound in a horn are configured to produce controlled, non-audible vibrations suitable for haptic feedback.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Speed

If horn structure is used for vibration devices, then natural frequency of 10-200 Hz is achieved suitable for haptic applications, but the device generates alarm sound which is not desired

Engineering Contradiction:
Improvenatural frequencyVSAvoidalarm sound
Core Design Contradiction:
SpeedVSObject-generated harmful factors

Solution Approach 1:

The resonator member responsible for sound generation is removed and replaced with a damping member. This allows the system to maintain its natural frequency in the 10-200 Hz range suitable for haptic applications while eliminating the alarm sound production.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the functional parameter of the member attached to the moving core from resonance (sound generation) to damping (vibration absorption). This parameter change allows the system to operate at the desired frequency range without generating unwanted sound.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If vibration device uses traditional structure, then it operates reliably, but it has greater number of components and smaller vibration intensity compared to horn

Engineering Contradiction:
Improveoperational reliabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the housing functions with the horn housing structure, integrating support, protection, and magnetic circuit containment into a single component. This reduces the total number of components while maintaining operational reliability through the proven horn design framework.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The housing is designed to serve multiple functions: structural support, magnetic circuit containment, and damping member mounting. This multi-functionality reduces component count while maintaining reliability, as the housing becomes a versatile platform for multiple system functions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 enables the vibration device to operate at a desirable frequency range for haptic applications, providing effective vibration notification without sound generation, while allowing for common manufacturing with horns.

Implementation Method 1

a coil in a ring shape disposed on the bottom portion of the housing and excited in response to energization

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The stator core and the moving core form a magnetic circuit between them in response to energization of the coil

Methodology Applied
Scientific EffectMagnetic force: Magnetic Field

Implementation Method 3

a leaf spring member having an outer circumferential portion fixed to an open end of the side portion of the housing, an inner circumferential portion fixed to the moving core, and a connecting portion connecting the inner circumferential portion and the outer circumferential portion, the leaf spring member being formed from a single plate of elastic material and biasing the moving core in a direction to separate from the stator core

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4640321A1Vibration device and vibration system
Publication Date: 2025.10.29 HAMANAKODENSO
  • EP4640321A1 patent drawingFigure 1~2
  • EP4640321A1 patent drawingFigure 3~4
  • EP4640321A1 patent drawingFigure 5~6

AI summary

A vibration device (100) has a leaf spring member (180) that is made of a single piece of elastic material and biases a moving core (160) in a direction that separates the moving core from a stator core (150). The leaf spring member (180) is a component corresponding to a diaphragm of a horn. The natural frequency of the vibration device (100) caused by vibration of the leaf spring member (180) and the moving core (160) is in a range 10-200 Hz. The natural frequency is a desirable frequency for vibrating a vibrated member as the vibration device (100). The vibration device (100) achieves the natural frequency that is favorable for the vibration device (100) by employing technology of the horn.