Patent ID: 7999429
Filing Date: 2011-08-16
Classification: F16D

Abstract:
1. A power transmission apparatus comprising: a pair of rotating bodies made of magnetic material, rotatable about different axes, and provided with a gap therebetween; a case enclosing the pair of rotating bodies; a pair of power transmission shafts connected coaxially with the pair of rotating bodies through the case, respectively; a magnetic fluid housed in the case to fill the gap; a magnetism generating device for generating magnetism; and a magnetic path forming device for forming a magnetic path of the magnetism generated by the magnetism generating device so that a magnetic field from one of the rotating bodies toward the other of the rotating bodies via the gap is generated, wherein a plurality of transmitting portions are provided between the pair of power transmission shafts, the pair of rotating bodies is disposed in each of the plurality of transmitting portions, a ratio of radiuses of rotation of the pair of rotating bodies is different between the transmitting portions, and the magnetic path forming device has a magnetic path switching device for selecting any one transmitting portion from the plurality of transmitting portions to form the magnetic path between the pair of rotating bodies in the transmitting portion and the magnetism generating device and for disconnecting the rotating bodies in the other transmitting portions which were not selected and the magnetism generating device from each other so that the magnetic path is not formed.