Magnetic Encoder Rotary Knob With Segmented Magnetic Detent
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Solution Overview
Problem
Existing encoder rotary knobs for magnetic encoders often allow the rotor to reach intermediate locking positions, leading to incorrect rotational positions due to the design of detent mechanisms.
Innovation Solution
A coaxial locking device comprising a segmented magnetic ring with alternating radial polarity and a toothed ring made of ferromagnetic material prevents intermediate locking positions by ensuring precise rotational alignment through magnetic interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spring-loaded balls are used in a detent mechanism, then the rotor can be locked in discrete positions, but the rotor can also stop in intermediate positions between detent recesses, leading to incorrect rotational positions
Solution Approach 1:
The magnetic ring is segmented into multiple magnetic segments with alternating polarity, creating discrete magnetic poles that interact with corresponding teeth on the rotor. This segmentation provides precise discrete locking positions while preventing intermediate stopping, as the magnetic attraction only occurs at specific aligned positions between the magnetic segments and rotor teeth.
Solution Approach 2:
The patent replaces the mechanical spring-loaded ball detent mechanism with a magnetic field-based locking system. The magnetic interaction between the segmented magnetic ring and the toothed rotor provides the detent effect without mechanical contact, eliminating the problem of intermediate positions while maintaining discrete rotational locking.
2Ease of manufacture
If holding magnets are used to attach the stator to the control surface, then installation without piercing the surface is enabled, but the magnetic force may not be sufficient for all materials
Solution Approach 1:
The patent uses magnets with adjustable strength and configuration to optimize the holding force for different control surface materials. The magnetic field parameters can be modified to ensure sufficient adhesion force while maintaining the non-piercing installation advantage, adapting to various materials like glass, glass ceramic, or stainless steel.
3Measurement precision
If a segmented magnetic ring with alternating polarity is used, then precise rotational positioning is achieved, but the device complexity increases
Solution Approach 1:
The patent combines the locking function and the position detection function into a single integrated structure. The segmented magnetic ring serves both to lock the rotor at precise positions and to provide detectable magnetic field variations for position sensing, eliminating the need for separate locking and detection mechanisms.
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 reliably prevents intermediate locking positions, ensuring accurate rotational positioning and easy installation without piercing the control surface, utilizing magnetic attraction for secure adhesion and a Hall sensor for position detection.
Implementation Method 1
one of the two rings is designed as a segmented magnetic ring with several magnetic ring segments, which are arranged with alternating radial polarity at equidistant angular intervals, and the other ring is formed as a toothed ring made of ferromagnetic material
Implementation Method 2
a magnet that interacts with the Hall sensor of the magnetic encoder
Implementation Method 3
The stator of this known rotary encoder knob is held on a control surface by means of magnetic force, in that holding magnets on the underside of the knob interact with magnets under the control surface
Data Source
Figure 1~2
Figure 3
AI summary
In an encoder knob (4) for a magnetic encoder (3), comprising a stator (8) for mounting on the top of a plate (2) made of non-magnetic material, in particular glass, glass-ceramic or stainless steel, with at least one holding magnet (14), a rotor (11) rotatably mounted on the stator (8) about a rotational axis (10) with a magnet (13) cooperating with a Hall sensor (6) of the magnetic encoder (3), and a detent device (15) acting between the stator (8) and the rotor (11), which specifies discrete rotational positions of the rotor (11), the detent device (15) is formed according to the invention by two rings arranged one inside the other and coaxially to the rotational axis (10), one of which is arranged on the stator (8) and the other on the rotor (11).One of the two rings is formed as a segmented magnetic ring (16) with several magnetic ring segments (18) which are arranged with alternating radial polarity at equidistant angular intervals, and the other ring is formed as a toothed ring (17) made of ferromagnetic material with several teeth (19) which are arranged at equidistant angular intervals, or also as a segmented magnetic ring with several magnetic ring segments which are arranged with alternating radial polarity at equidistant angular intervals.