Design and construction of permanent magnetic gears

Frank Thorleif Jørgensen

Research output: Book/ReportPh.D. thesis

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This thesis deals with design and development of permanent magnetic gears. The goal of this thesis is to develop knowledge and calculation software for magnetic gears. They use strong NdFeB permanent magnets and a new magnetic gear technology, which will be a serious alternative to classical mechanical gears. The new magnetic gear will have a high torque density1 relationship –high efficiency and are maintenance free. In this project was manufactured two test gears which is tested and verified with models developed in this project.

Present technological status for magnetic gears is introduced in a state of the art analysis. Furthermore made an analysis for mechanical gears in order to estimate performance characteristic compared to traditional mechanical gears was created.

Some of the gear types found at the state of the art analysis are chosen for further investigation. Analytical and numerical calculation models for determination of gear output torque from different magnetic gear types are analysed. These analytical calculations models are used together with optimisation tools in order to improve the performance of investigated magnetic gear types. Experimental test gears are designed to validate the calculation models.

The first gear type is the very basic magnetic spur gear, which reminds most of all of the traditional mechanical spur gear, the difference is basically that magnetic teeth is replacing mechanical teeth. A magnetic version of the spur gear with a gearing of 1:4 will be able to reach an active torque density of approximately 24 [Nm/l]. Corresponding mechanical spur gears examples with a gearing of 1:5 are found and these gears have a total torque density of 16 to 24 [Nm/l].

The second analysed gear type is the magnetic version of the traditional cycloidal gear. This magnetic gear type is searched and only a single reference [74] is found and that is why the combination of a cycloidal gear and a magnetic gear are considered as an innovative supplement to magnetic gear technology. A magnetic cycloidal gear is designed with a gearing of 1:21 and a calculated active torque density of 142 [Nm/l]. Measurement from this gear has resulted in a measured total torque density of 23 [Nm/l]. Mechanical versions of this gear type are found with total torque density in the 16 to 31 [Nm/l] range. The third and last gear technology that is investigated is a gear that reminds of a planetary gear. Research shows that this gear technology is also one of better technologies regarding torque density.
Original languageEnglish
PublisherDepartment of Energy Technology, Aalborg University
Number of pages127
ISBN (Print)978-8789179-86-5
Publication statusPublished - 2010


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