Magnetic Hysteresis Brake Pole Layout for Reduced Elastic Return
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Solution Overview
Problem
Magnetic hysteresis brakes exhibit a significant magnetic elastic return that causes the rotor to move away from the intended position after release, leading to inaccurate motor control, and increasing the number of magnetic poles to reduce this return increases the brake's bulk and mass.
Innovation Solution
The brake design incorporates magnetic elements, such as teeth, made of a magnetic flux-conducting material with a polarity opposite to the magnets, which separate and optimize the magnetic flux, allowing for a higher number of poles without increasing the overall size, and includes a framework with magnets mounted between teeth to enhance flux loop-back.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of magnetic poles is increased to reduce magnetic elastic return, then the magnetic elastic return amplitude is reduced, but the bulk and mass of the magnetic hysteresis brake increase proportionally
Solution Approach 1:
The magnetic circuit is segmented into alternating magnetic poles and magnetic elements with opposite polarity. This segmentation allows the magnetic flux to be divided into multiple paths, increasing the effective number of poles without proportionally increasing the overall size of the brake assembly.
Solution Approach 2:
Magnetic elements with polarity opposite to the magnets are introduced as intermediary components between adjacent magnets. These elements serve dual functions: they create additional magnetic flux paths (effectively increasing pole count) and provide magnetic flux loop-back that reduces magnetic elastic return, all while occupying minimal space.
2Measurement precision
If the number of magnetic poles is increased to reduce magnetic elastic return, then the magnetic elastic return amplitude is reduced, but the complexity of the magnetic circuit increases
Solution Approach 1:
The magnetic elements are integrated into the existing magnetic circuit structure, merging their flux-conducting function with the overall magnetic path design. This consolidation allows the increased pole count to be achieved without proportionally increasing structural complexity, as the magnetic elements become part of the unified magnetic circuit rather than separate additions.
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 design reduces the magnetic elastic return amplitude while maintaining optimal magnetic performance, ensuring precise control and reducing the brake's bulk and mass.
Implementation Method 1
when the material is subjected to an excitation magnetic field, a magnetic field is induced in the material
Implementation Method 2
when the excitation field varies, the corresponding induced field describes a hysteresis cycle
Implementation Method 3
magnetic elements which are made of a magnetic flux-conducting material and which have a first surface facing the first surface of the second member and adjacent to the first surface of the adjacent first magnets to let pass a second magnetic flux the direction of which is opposite to the first flux
Data Source
AI summary
A magnetic hysteresis brake (10), comprising at least a first member (11.1) carrying first magnets (17.1) and a second member (12) made of magnetic material, each first magnet having a first surface (15.1) facing a first surface (14) of the second member (12) in order to generate a first magnetic flux towards the second member (12) through said surfaces, characterised in that the first magnets (17.1) are separated from one another by magnetic elements (18.1) which are made of a magnetic flux-conducting material and which have a first surface facing the first surface (14) of the second member (12) and close to the first surface (15.1) of the adjacent first magnets (17.1) in order to let pass a second magnetic flux the direction of which is opposite to the first flux of the first adjacent magnets, the first surface of the magnetic elements being of smaller size than the first surface (15.1) of the first magnets. The invention also relates to a control instrument and to a vehicle comprising such a brake.