Induction Housing Repulsive Force for Motor Stiffness

Solution Overview

Problem

Synchronous motors in hard drive technology suffer from reduced stiffness due to attractive forces, leading to sub-optimal performance.

Innovation Solution

Replacing the permanent magnet with an induction housing, also known as a squirrel cage, which induces a current and generates a repulsive force when rotating within a magnetic field, thereby increasing stiffness and stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If synchronous motors use permanent magnets, then the motor can operate, but the attractive forces reduce stiffness and lead to sub-optimal performance

Engineering Contradiction:

ImprovestiffnessVSAvoidattractive force

Core Design Contradiction:

Stability of the object's compositionVSForce

Solution Approach 1:

The patent inverts the conventional synchronous motor approach by replacing the permanent magnet with an induction housing (squirrel cage). Instead of using attractive forces between permanent magnets and electromagnets, the system uses repulsive forces generated by induced currents in the squirrel cage interacting with the electromagnet's magnetic field. This inversion of the force mechanism resolves the stiffness problem while maintaining motor functionality.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent replaces the permanent magnet mechanical component with an induction housing that operates on electromagnetic induction principles. The squirrel cage structure with conductive bars and end rings substitutes the permanent magnet, allowing current induction and repulsive force generation instead of direct magnetic attraction, thereby improving stiffness.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Power

If permanent magnets are used in the motor, then the motor generates rotational force, but the attractive forces reduce system stability

Engineering Contradiction:

Improverotational forceVSAvoidstability

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The patent inverts the conventional synchronous motor approach by replacing the permanent magnet with an induction housing (squirrel cage). Instead of using attractive forces between permanent magnets and electromagnets, the system uses repulsive forces generated by induced currents in the squirrel cage interacting with the electromagnet's magnetic field. This inversion of the force mechanism resolves the stiffness problem while maintaining motor functionality.

Inventive Principle:

Principle #13The other way round (Inversion)

3Quantity of substance

If storage density is increased, then more data can be stored, but the size of the storage system decreases

Engineering Contradiction:

Improvestorage densityVSAvoidsystem size

Core Design Contradiction:

Quantity of substanceVSVolume of moving object

Solution Approach 1:

The patent changes the fundamental operating parameter of the motor from attractive force (synchronous motor) to repulsive force (induction motor with squirrel cage). This parameter change enables improved stiffness and stability, allowing the motor to maintain performance in a more compact configuration, thereby supporting higher storage density in smaller form factors.

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 repulsive force enhances the stiffness and stability of the disk drive system, improving overall performance by increasing the rotational stiffness and stability of the motor.

Implementation Method 1

A current is induced within the induction housing resulting from the relative rotation. The induced current creates a repulsive force between the stationary component and the hub.

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS9196294B2Apparatus with repulsive force between stationary and rotatable components

Publication Date: 2015.11.24 EVAULT INC

AI summary

Provided herein, is an apparatus that includes a fluid dynamic bearing, a hub, and an induction housing. The fluid dynamic bearing is defined by a stationary component and a rotatable component. The hub is configured to rotate relative to the stationary component. A current is induced within the induction housing resulting from the relative rotation. The induced current creates a repulsive force between the stationary component and the hub.