Scalable Hysteresis Coupling Design for Torque and Size Adaptability
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Solution Overview
Problem
Existing hysteresis clutches are limited in their ability to be constructed in various sizes and applications, as they are typically designed for specific sizes and do not allow for flexible implementation in different contexts.
Innovation Solution
A hysteresis clutch design featuring two rotors with permanent magnets of different coercivity, a frusto-conical or cylindrical air gap, and a second rotor constructed with multiple individual permanent magnets arranged in a discontinuous row, enabling the creation of clutches of any size, including high-torque and compact designs with low moment of inertia.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the second rotor is designed as a continuous hysteresis material structure, then the coupling can transmit high torque, but the coupling cannot be constructed in various sizes and applications
Solution Approach 1:
The second rotor is divided into multiple discrete permanent magnets arranged in a circumferential pattern instead of using continuous hysteresis material. This segmentation allows the coupling to be manufactured in different sizes by varying the number and arrangement of magnets while maintaining effective torque transmission through the magnetic field interaction between the two rotors
2Strength
If the motor-side rotor has a large size with ceramic magnets, then the moment of inertia is higher, but the radial stray field induces eddy currents in the clutch housing
Solution Approach 1:
A magnetic shielding structure (tuning band) is introduced as an intermediary element between the motor-side rotor and the clutch housing. This shielding structure guides and contains the radial stray field, preventing it from inducing eddy currents in the clutch housing while maintaining the strong magnetic field necessary for torque transmission
3Adaptability or versatility
If permanent magnets with different coercive field strengths are used in both rotors, then the coupling can be constructed in various sizes, but the device complexity increases
Solution Approach 1:
The patent utilizes changes in magnetic parameters (coercive field strength) of the permanent magnets to achieve size scalability. By selecting magnets with appropriate coercive field strengths for different rotor positions and sizes, the coupling can be adapted to various applications while managing complexity through parameter optimization rather than structural complexity
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 allows for the construction of hysteresis clutches in a wide range of loads and applications, achieving high transmissible torque with low weight and minimizing stray field effects, enabling high speeds and a compact, efficient design.
Implementation Method 1
two rotors, each equipped with several permanent magnets of different coercive field strengths. A frustoconical or, preferably, a cylindrical air gap is formed between the two rotors
Implementation Method 2
hysteresis coupling, in particular for the transmission of torques in machines and systems
Implementation Method 3
two rotors, each equipped with several permanent magnets of different coercive field strengths
Implementation Method 4
A frustoconical or, preferably, a cylindrical air gap is formed between the two rotors
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The hysteresis clutch (10) according to the invention is provided with a first rotor (11) with magnets (18) which are polarized in opposite directions in pairs in the circumferential direction and between which pole pieces (17) are provided for deflecting the magnetic flux in the radial direction. A second rotor (12) has a series of second permanent magnets (19) which extend in the circumferential direction and which are arranged on a circle that is concentric to the rotational axis A. The number of the first magnets (18) and the number of the second magnet (19) are configured such that a smooth torque curve is achieved which is free of a detent torque or at least has a low detent torque. For this purpose, the number (M) of permanent magnets of the first rotor and the number of permanent magnets (S) of the second rotor are configured while taking into consideration one another and while maintaining specific conditions. For this purpose, the two numbers (M) and (S) can be configured in accordance with at least one of the two following conditions: the two numbers (M) and (S) are mutually prime, and/or the product of the two numbers (M) and (S) divided by 180 is a whole-number exponent of the number two (M*S/180=2N, [N=0, 1, 2, 3...]).