Patent ID: 6524006
Filing Date: 2003-02-25
Classification: F16C,G11B,H02K

Abstract:
A bearing assembly for a disk drive motor including:a shaft, said shaft having a circumferential surface; a thrust plate projecting annularly outward from said circumferential surface, said thrust plate having a first annular surface substantially perpendicular to said circumferential surface; a housing arranged around said shaft and said thrust plate, said housing having a first surface opposing said circumferential surface and forming a first gap therebetween, said housing also having a second surface opposing said annular surface and forming a second gap therebetween, said first gap and second gap being in fluid communication; a fluid or a combination of fluids located within said first and second gaps for lubricating purposes; a first set of grooves on at least one of said circumferential surface and said first surface; a second set of grooves on at least one of said annular surface and said second surface, wherein each of said grooves is shaped so as to have at least one pair of legs, said legs converging to form at least one apex, wherein one of said legs is longer than the other and forms an asymmetry, whereby said pumping action is created by said asymmetry, and said first and second sets of grooves are oriented to create competing first and second pumping actions, respectively, on said fluid when said bearing housing rotates around said shaft, said first pumping action tending to pump said fluid out of said second gap, and said second pumping action counteracting said first pumping action.