Power transmission device

Abstract

A power transmission device includes: a high speed magnet rotor which includes a magnet array which is magnetized in a radial direction; a low speed magnet rotor which includes a magnet array which is magnetized in a circumferential direction; and an inductor rotor which allows magnetic fluxes from the magnet array of the high speed magnet rotor to pass, and the high speed magnet rotor, the low speed magnet rotor and the inductor rotor are concentrically arranged and the magnet array of the low speed magnet rotor is formed such that homopolar surfaces of neighboring magnets face each other in the circumferential direction.

Description

BACKGROUND[0001]1. Technical Field[0002]The present invention relates to a power transmission device which uses magnetism.[0003]2. Description of Related Arts[0004]In the past, a power transmission device which is generally used uses a mechanical gear mechanism whose gears of a drive shaft and a driven shaft enmesh with each other. A power transmission device which uses a gear mechanism transmits power while gears directly contact each other, and therefore causes noise and vibration and hardly has a long service life. Further, a power transmission device which uses a gear mechanism needs to be maintained on a regular basis to suppress an increase of noise and vibration due to a secular change and minimize abrasion of gears. Maintenance of a power transmission device which uses a gear mechanism is limited needs to be taken into account, and therefore the place to install the power transmission device is limited and the degree of freedom of design is restricted.[0005]In recent years, ...

AI Technical Summary

Benefits of technology

The present invention aims to provide a power transmission device that is small and can achieve greater torque and a wide range of acceleration and deceleration ratios. The invention achieves this by aligning magnetic fluxes passed through a low speed magnet rotor, which reduces leakage magnetic fluxes and increases the amount of magnetic flux that passes through the rotor. This results in a more efficient power transmission between the rotor and the load.

Problems solved by technology

A power transmission device which uses a gear mechanism transmits power while gears directly contact each other, and therefore causes noise and vibration and hardly has a long service life.

Maintenance of a power transmission device which uses a gear mechanism is limited needs to be taken into account, and therefore the place to install the power transmission device is limited and the degree of freedom of design is restricted.

However, according to the magnetic accelerating / decelerating device disclosed in US 2011 / 0057456, an area in which the magnet of the high speed rotor and the magnet of the low speed rotor oppose to each other needs to be made larger to further increase the allowable torque, and therefore the magnetic accelerating / decelerating device inevitably becomes larger.

In addition, when an area in which a magnet of a high speed magnet rotor and a magnet of a low speed rotor oppose to each other is increased in a small magnetic accelerating / decelerating device, a pitch between the magnets of the low speed rotor inevitably becomes longer.

When the pitch becomes longer, the number of magnets of the low speed rotor which can be arranged on the same circumference decreases, and therefore the acceleration and deceleration ratio of the magnetic accelerating / decelerating device cannot be increased.

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