Linear Vibration Motor Magnetic Stabilization
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Solution Overview
Problem
Conventional linear vibration motors face challenges in reducing thickness and width while preventing actuation noise and maintaining stabilized operation, especially in miniaturized electronic devices, due to the need for high-precision assembly of guide shafts which hinders productivity.
Innovation Solution
The design incorporates a movable element with a magnet, weight, and yoke, along with a frame and coil, featuring a magnetic material portion on the frame's inner surface and a raised portion on the yoke to stabilize the movable element's orientation, eliminating the need for two guide shafts and allowing for reduced thickness and width, thus preventing noise and improving manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If two guide shafts are provided to suppress rolling of the movable element, then stabilized linear vibration is achieved, but the width of the linear vibration motor becomes wide and assembly precision requirements increase
Solution Approach 1:
The patent removes the two guide shafts from the structure entirely. Instead of using mechanical shafts to constrain the movable element, the invention relies on the magnetic field interaction between the magnet on the movable element and the magnetic material portion on the frame, combined with the elastic restoring force of the elastic member, to achieve stable linear vibration without requiring lateral constraint structures that increase width.
Solution Approach 2:
The patent replaces the mechanical guide shaft constraint system with a magnetic field-based positioning system. The magnetic attraction between the magnet and magnetic material portion, combined with the elastic member's restoring force, substitutes for the mechanical guidance function of the guide shafts, eliminating the need for high-precision mechanical assembly of parallel shafts.
2Length of moving object
If the movable element is formed into a flat shape to reduce thickness, then thickness reduction is achieved, but the movable element rotates around the linear vibrational axis causing actuation noise and rattling
Solution Approach 1:
The patent introduces a magnetic material portion on the frame as an intermediary that interacts magnetically with the magnet on the movable element. This magnetic interaction serves as a mediator to stabilize the orientation of the flat movable element during vibration, preventing rotation around the vibrational axis without requiring mechanical guide structures that would increase thickness.
Solution Approach 2:
The patent changes the physical state and interaction parameters by utilizing magnetic field forces instead of mechanical contact forces. The magnetic attraction between the magnet and magnetic material portion, combined with the elastic restoring force, creates a stable equilibrium position that prevents rotational movement of the flat movable element during linear vibration.
3Reliability
If two stationary shafts are provided on both sides of the magnet, then stabilized vibration is achieved, but the width increases and productivity decreases due to high-precision assembly requirements
Solution Approach 1:
The patent removes the two stationary shafts from the structure. The stabilization function previously provided by the shafts is achieved through the magnetic field interaction between the magnet and magnetic material portion, combined with the elastic restoring force of the elastic member, eliminating the need for complex mechanical assembly procedures.
Solution Approach 2:
The patent replaces the mechanical shaft-based stabilization system with a magnetic field-based system. This substitution eliminates the requirement for high-precision mechanical assembly of parallel shafts, as the magnetic and elastic forces naturally provide the necessary stabilization, thereby significantly improving assembly productivity.
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
This configuration enables a compact, noise-free linear vibration motor with reduced thickness and width, enhancing productivity by eliminating the need for high-accuracy assembly and maintaining stable vibration without rattling, while allowing for adequate driving force and space efficiency in mobile devices.
Implementation Method 1
an electric current is applied to a coil that is provided on the stator side to cause the Lorentz forces that act on the magnet to form a driving force
Implementation Method 2
an elastic member for applying, to the movable element, an elastic force that opposes the driving force that is applied to the magnet portion
Implementation Method 3
a magnetic material portion that extends along the direction of vibration of the movable element is provided on an inner surface of the frame, and the yoke has a raised portion near the magnetic material portion
Data Source
AI summary
A linear vibration motor comprises: a movable element that comprises a magnet portion, a weight portion, and a yoke; a frame for enclosing the movable element; a coil, secured to the frame, for applying a driving force to the magnet portion so as to cause the movable element to undergo reciprocating vibration along the axial direction; and an elastic member for applying, to the movable element, an elastic force that repels the driving force that is applied to the magnet portion, wherein: a magnetic material portion (a magnetic material piece) that extend along the direction of vibration of the movable element is provided on an inner surface of the frame, and the yoke has a raised portion near the magnetic material portion (the magnetic material piece).