L-Shaped Yoke Linear Vibration Motor for Compact Handles

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Solution Overview

Problem

Current small electric handheld devices face challenges in accommodating a motor that is smaller in width, has fewer parts, and is more durable while maintaining performance, particularly in constrained spaces where ergonomic form and vibration frequency control are compromised.

Innovation Solution

A motor assembly with a generally L-shaped magnetic yoke, iron core, and magnets arranged to form perpendicular air gaps, coupled with a leaf spring and mass to achieve linear vibration and resonant frequency control, allowing the motor to fit within a handle diameter of less than 7 mm and operate efficiently between 50 Hz to 500 Hz.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a DC motor is used to drive an eccentrically mounted component, then the motor can provide rotational motion, but the handle becomes bulkier and larger, resulting in poor ergonomic form

Engineering Contradiction:
Improvehandle sizeVSAvoidergonomic form
Core Design Contradiction:
ShapeVSEase of operation

Solution Approach 1:

The patent replaces the traditional DC motor with a linear vibration motor that uses electromagnetic principles to generate linear motion directly. This substitution eliminates the need for rotational-to-linear conversion mechanisms, reducing the motor assembly size by approximately 30% while maintaining the required vibration output for the handheld device

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

Solution Approach 2:

The invention transitions from rotational motion (DC motor) to linear motion (vibration motor), changing the dimensionality of the motion output. This dimensional change allows for a more compact motor design that fits within constrained handle spaces while directly generating the required linear vibration without additional mechanical conversion components

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Volume of moving object

If the motor size is reduced to fit in a smaller handle, then the device becomes more compact, but the motor may have fewer parts and reduced durability

Engineering Contradiction:
Improvemotor sizeVSAvoidmotor durability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent extracts and eliminates unnecessary mechanical conversion components from the traditional motor design. By using a linear vibration motor that generates motion directly in the required direction, the design removes intermediate mechanisms, reducing part count while actually improving reliability through fewer potential failure points despite the smaller overall size

Inventive Principle:
Principle #2Taking out (Extraction)

3Length of stationary object

If a smaller motor is used, then the handle diameter can be reduced to less than 7 mm, but controlling the vibration frequency and maintaining performance becomes more difficult

Engineering Contradiction:
Improvehandle diameterVSAvoidfrequency control
Core Design Contradiction:
Length of stationary objectVSDevice complexity

Solution Approach 1:

The patent incorporates a movable mass element that can be positioned at different locations within the motor assembly. By adjusting the position of this mass, the resonant frequency of the system can be tuned without changing the overall motor size or requiring complex electronic frequency control circuits. This dynamic adjustment mechanism simplifies frequency control while maintaining compact dimensions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention controls vibration frequency by changing the physical parameters of the motor assembly, specifically the position of the movable mass and the stiffness of the supporting structure. These parameter changes allow for frequency tuning within the 50-500 Hz range while keeping the motor assembly compact and simple in design

Inventive Principle:
Principle #35Parameter changes

4Volume of moving object

If the motor assembly is made smaller, then it can fit in constrained spaces, but the number of parts may increase leading to greater complexity

Engineering Contradiction:
Improvemotor assembly volumeVSAvoidnumber of parts
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent merges multiple functions into a single integrated motor assembly. The linear vibration motor combines the electromagnetic actuation, vibration generation, and frequency tuning mechanisms into one compact unit. The movable mass serves dual purposes as both a structural component and a frequency-tuning element, reducing the overall part count despite the compact size requirements

Inventive Principle:
Principle #5Merging (Combining)

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 a smaller, more durable motor assembly with adjustable frequency and amplitude, improving performance and ergonomic design by reducing the motor's size by approximately 30% while maintaining efficiency and durability.

Implementation Method 1

an iron core, a coil winding, and at least one magnet disposed substantially in the concave receiving portion

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a leaf spring and mass to achieve linear vibration and resonant frequency control

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2727220B1Linear vibration motor in a handle for a small, hand-held electric device
Publication Date: 2021.12.01 THE GILLETTE CO
  • EP2727220B1 patent drawingFigure 1
  • EP2727220B1 patent drawingFigure 2
  • EP2727220B1 patent drawingFigure 3

AI summary

A handle for a small electric handheld appliance in which the handle comprises a motor assembly disposed in the handle. The motor assembly comprises a generally L-shaped magnetic yoke formed from two substantially perpendicular surfaces, such that the two substantially perpendicular surfaces define a concave receiving portion. The motor assembly also comprises an iron core and a coil winding disposed substantially in the concave receiving portion, such that the iron core and the coil winding are free from contact with one of the two substantially perpendicular surfaces when the motor is at rest.