Patent ID: 6105943
Filing Date: 2000-08-22
Classification: F16F,H02K

Abstract:
An active damping oscillator comprising:a shaft member;an outer sleeve disposed radially outwardly and independently of said shaft member and axially movable relative to said shaft member;a plurality of first magnetic pole portions disposed fixedly to one of said shaft member and said outer sleeve;at least one permanent magnet associated with said first magnetic pole portions to give magnetic poles to said first magnetic pole portions;a plurality of second magnetic pole portions disposed fixedly to the other of said shaft member and said outer sleeve; andat least one coil associated with said second magnetic pole portions and energized to give magnetic poles to said second magnetic pole portions,and wherein said first magnetic pole portions and said second magnetic pole portions are opposed to each other in a radial direction of said shaft member with a predetermined radial gap therebetween, and are offset from each other in an axial direction of said shaft member such that said shaft member is held in a predetermined neutral axial position by first magnetic forces of said first magnetic pole portions which act between said first magnetic pole portions and said second magnetic pole portions, while said at least one coil is in a non-energized state, and such that said shaft member and said outer sleeve are moved relative to each other in said axial direction against said first magnetic forces by second magnetic forces which are generated upon energization of said at least one coil and which act between said first magnetic pole portions and said second magnetic pole portions.