Towards Miniaturization of Magnetic Gears: Torque Performance Assessment

Abstract

Magnetomechanical components can be a good solution in order to reduce, or even completely avoid, friction phenomena in micro-electro-mechanical systems (MEMS) since they can transmit forces through magnetic fields without contacts. In this communication, electromagnetic simulations of the expected specific torque of a coaxial magnetic gear are given. The results show that micromagnetic gears (3 mm of diameter) could provide a specific torque up to 8.98 Nm/kg, several times larger than the specific torque that microgears (<9 mm of diameter) can provide. This implies that micromagnetic gears could provide speed conversion without contact in the teeth, avoiding corresponding friction, but also that it would even improve the specific torque transmission with respect to contact microgears.

Desarrollo de una máquina bobinadora semiautomática para la microfabricación de bobinados, antenas y solenoides micrométricos

“…En los MEMS se requieren subsistemas y componentes capaces de generar o recibir señales electromagnéticas. En el caso de los actuadores electromagnéticos, son necesarios elementos inductores capaces de generar el campo magnético necesario para actuar mecánicamente sobre imanes permanentes de alta calidad [19]- [20] , que han demostrado ser reducibles a la escala microscópica [21]- [22]. En el caso de los transductores electromagnéticos, es necesario emitir y recibir señales de radiofrecuencia a través de antenas con la suficiente potencia y ganancia, y bajo coeficiente de reflexión.…”

Simplified Design of Magnetic Gear by Considering the Maximum Transmission Torque Line

“…Surface-type PMs are used at both high-speed and low-speed rotors where the PMs are attached on the arc surface of the iron yoke of the rotors. The surface-type PM has a lower torque ripple compared with the interior-type PM [20]. Thus, the surface of the PMs is curved where the pole directions are outwards and inwards of the arc and are alternately arranged.…”

“…To prove that the MTTL is relevant for designing surface type magnetic gear, it was tested with a few magnetic gear models, using Equation (20). Thus, five models of magnetic gears were randomly designed with different conditions, to validate the relevancy of the proposed approach, considering the MTTL.…”

Microfabrication of Sm2Co17 micromagnets for MEMS and micromotors using ultrashort pulsed hydro laser micromilling process

“…Permanent magnets made of NdFeB and SmCo can reach high magnetic products, high remanence and high coercitivity. Theses magnets are used in plenty of industrial applications: electric machines [1], mechanical damping [2] [3], braking [4] or contactless transmission [5] systems. In MEMS (Micro-ElectroMechanical Systems) [6][7][8] and micromachines [9][10][11][12], high quality magnets of NdFeB and SmCo in micrometric size are required.…”