Haptic Actuator Elastic Element With Magnetic Particles

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Solution Overview

Problem

Conventional haptic actuators used in vehicles lack sufficient magnetic field intensity and sensitivity in force measurement, resulting in less effective tactile feedback and vibration amplitude, which can lead to accidental function triggering and suboptimal user experience.

Innovation Solution

Incorporating magnetic particles into the elastic element of the haptic actuator increases its magnetic permeability, enhancing the circulation and intensity of the magnetic field, thereby increasing the force exerted on the movable part and improving tactile feedback and force measurement sensitivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If magnetic particles are added to the elastic element, then magnetic permeability and magnetic field circulation are improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvemagnetic field intensityVSAvoiddevice complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The elastic element is formulated as a composite material incorporating magnetic particles (such as iron oxide or neodymium particles) dispersed within an elastic matrix (silicone or rubber). This composite structure provides both the elastic restoring force and enhanced magnetic permeability, allowing the single component to fulfill dual functions without adding separate magnetic elements to the actuator assembly.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The magnetic permeability of the elastic element is adjusted by varying the concentration, size, and distribution of magnetic particles within the elastic matrix. By changing these parameters, the elastic element's magnetic properties can be optimized to enhance magnetic field circulation and intensity while maintaining the desired elastic characteristics and restoring force.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If magnetic particles are loaded into the elastic element, then force measurement sensitivity is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveforce measurement sensitivityVSAvoidmanufacturing precision
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The sensitivity of force measurement is enhanced by optimizing the magnetic particle concentration and distribution within the elastic element. By adjusting these parameters, the elastic element's magnetic permeability varies more significantly with compression, amplifying the capacitive or inductive signal changes that correspond to applied force, thereby improving measurement sensitivity.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces direct mechanical force sensing with indirect capacitive or inductive measurement. The magnetic particles in the elastic element modulate the magnetic field, which in turn affects the capacitance or inductance of nearby sensors. This substitution allows for more sensitive and contactless force measurement while reducing wear and mechanical complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enhanced magnetic field circulation results in clearer and more pronounced tactile sensations and increased vibration amplitude, while also improving the sensitivity of force measurement, providing a better user experience and preventing accidental function triggering.

Implementation Method 1

a stator (110), a movable part (140) and at least one elastic element (151, 152)... a winding of electric wire (125) forming a coil (120) being capable of producing a magnetic field when a current flows through the electric wire

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the presence of the magnetic particles increases the magnetic permeability of the elastic element, which improves the circulation of a magnetic field between the moving part and the stator

Methodology Applied
Scientific EffectMagnetic permeability:

Implementation Method 3

a winding of electric wire (125) forming a coil (120) being capable of producing a magnetic field when a current flows through the electric wire, and a magnetic circuit which partly envelops said coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

a movable part (140) at least partly made of ferromagnetic material so as to be attracted by the magnetic field

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Implementation Method 5

a restoring force which tends to repel the moving part... The elastic element is then compressed and in return exerts a restoring force

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 6

It is possible to measure the distance between the moving part and the stator (and therefore indirectly the force exerted on the touch surface) capacitively or inductively

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 7

an electrical circuit is connected to the coil so as to carry out an inductive measurement of the distance between the stator and the movable part

Methodology Applied
Scientific EffectInductance: Inductor

Data Source

PatentEP3995936B1Haptic actuator for touch-sensitive surface
Publication Date: 2024.09.04 VALEO COMFORT & DRIVING ASSISTANCE
  • EP3995936B1 patent drawingFigure 1~2

AI summary

The invention relates to a haptic actuator (100) for a touch surface (141) comprising a stator (110), a moving part (140) and at least one elastic element (151, 152), said stator (110) comprising a winding of electric wire (125) forming a coil (120) being capable of producing a magnetic field when a current flows through the electric wire (125), and a magnetic circuit (130) which partially encloses said coil (120), said moving part (140) being at least partially made of ferromagnetic material so as to be attracted by the magnetic field, said elastic element (151, 152) being interposed between the magnetic circuit (130) and the moving part (140) so as to repel the moving part (140) when the latter is attracted towards the stator (110) by the magnetic field. According to the invention, said elastic element (151, 152) is loaded with magnetic particles (155).