Optical Filter Wheel Magnetic Drive Without Gear Wear
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing motor driven optical filter wheels face issues with wear due to gear systems and potential magnetic interference from permanent magnets, particularly in sensitive environments like satellites.
Innovation Solution
A motor driven optical element exchange unit utilizing soft magnetic teeth and a permanent magnet to provide both static hold force and rotation force without a gear transmission, using a stator with two soft magnetic yokes and a permanent magnet for direct wheel rotation and positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a gear system is used to couple the motor to the wheel, then the motor can be placed next to the gear system within the radius of the wheel, but wear is generated due to the gear system
Solution Approach 1:
The patent replaces the mechanical gear system with a magnetic coupling system. Electromagnets on the stator interact magnetically with the permanent magnet on the rotor to produce rotational motion, eliminating mechanical gears and their associated wear while maintaining the ability to couple the motor to the wheel within the wheel's radius.
2Ease of operation
If a permanent magnet is used in the stepper motor, then the filter wheel can be held in position when no current is supplied, but magnetic interference occurs in environments with sensitive electronics or satellites
Solution Approach 1:
The patent extracts the permanent magnet from the traditional stepper motor configuration and relocates it to the rotor. The stator uses electromagnets instead of permanent magnets, allowing the holding position function to be achieved through magnetic coupling while reducing the magnetic field source in the stator that causes interference with sensitive electronics.
Solution Approach 2:
The patent introduces a magnetic coupling mechanism as an intermediary between the stator electromagnets and the rotor permanent magnet. This magnetic field acts as a mediator to transmit force and hold position without requiring the stator to contain a permanent magnet that would generate harmful magnetic interference.
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
Minimizes wear and magnetic interference, allowing precise positioning and smooth rotation of optical elements while reducing the need for additional magnetic fields, suitable for environments with sensitive electronics or satellites.
Implementation Method 1
a permanent magnet, magnetically coupled between parts of the first and second soft magnetic yoke
Implementation Method 2
first soft magnetic teeth protruding from a soft magnetic part of the wheel at even angular offset along at least part of a ring around a rotation axis of the wheel
Data Source
AI summary
An optical element exchange unit, has a rotatable wheel e.g. with different filters. The wheel has first soft magnetic teeth protruding from a soft magnetic part of the wheel at even angular offset along at least part of a ring around a rotation axis of the wheel. The optical element exchange unit has a stator comprising a first soft magnetic yoke, the first soft magnetic yoke having poles with a first group and second group of at least one second soft magnetic tooth respectively, the second soft magnetic teeth of the first and second group protruding from the poles of the first soft magnetic yoke towards the first soft magnetic teeth and a second soft magnetic yoke, the second soft magnetic yoke having poles with a third group and fourth group of at least one second soft magnetic tooth respectively, the second soft magnetic teeth of the third and fourth group protruding from the poles of the second soft magnetic yoke towards the first soft magnetic teeth. A permanent magnet is magnetically coupled between parts of the first and second soft magnetic yoke. The teeth of the first, second, third and fourth groups are positioned so that, when each tooth of the first group is aligned with its nearest first soft magnetic tooth, each second soft magnetic tooth of the second group is halfway the angular offset between its nearest first soft magnetic teeth, and the second soft magnetic teeth in the third and fourth group are less than half the angular offset in opposite directions from their nearest first soft magnetic teeth.