Patent ID: 7084538

Claim:
A bearing assembly comprising: a guide having a top side provided with a guide surface comprising a magnetic body; a moving body which moves along the guide surface; a first movable guide which moves along the guide surface and moves said moving body in a first direction; a second movable guide which moves along the guide surface and moves said moving body in a second direction which is orthogonal to the first direction; a bearing provided on a portion of said first and second movable guides that opposes the guide surface; and a magnet, which has an opposing surface that opposes the guide surface, provided on said first and second movable guides for the purpose of applying a magnetic attractive force between said first and second movable guides and the guide surface, wherein a relationship of the size and/or placement of the guide surface and the opposing surface of said magnet is defined for the purpose of limiting displacement of said first and second movable guides in a width direction, which is orthogonal to a travelling direction of each of said first and second movable guides, to an allowable range, using a magnetic attractive force in the width direction produced in accordance with an amount of deviation of the opposing surface of said magnet from the guide surface owing to displacement, which can occur when each of said first and second movable guides moves in the width direction, and wherein a size of the guide surface in the width direction is defined by a groove, which extends along the traveling direction, provided in the top side of said guide, and a terminus, which extends along the traveling direction, of the top side of said guide.