Cross-linear slide bearing having reduced thickness for use in X-Y table

Claim 1

A cross-linear slide bearing having a reduced thickness for use in an X-Y table comprising: a pair of first track rails which are disposed on a securing part such as to be in parallel to each other and are respectively provided in the opposing inner surfaces thereof with loaded ball rolling grooves extending longitudinally; a pair of second track rails which are attached to a movable table such as to be in parallel to each other and to cross said first track rails at right angles and are provided in the opposing inner surfaces thereof with loaded ball rolling grooves extending longitudinally; and four bearing units which are respectively disposed at intersections between said first and second track rails and are adapted to linearly move relative to the corresponding track rails, wherein each of said bearing units is composed of: a flat bearing body having a pair of outer side surfaces which are adjacent to each other at 90 degrees, said bearing body having first and second loaded ball rolling grooves which are respectively formed in said outer side surfaces such as to face the corresponding loaded ball rolling grooves on said first and second track rails and such as to be separate from each other vertically, said bearing body further having a non-loaded ball rolling groove which is provided horizontally inward of each of said first and second loaded ball rolling grooves and is connected to the corresponding loaded ball rolling groove, thereby forming an endless ball rolling passage for recirculating balls; a multiplicity of balls disposed within said endless ball rolling passage; and a ball retainer which is attached to said bearing body and is adapted to rollably retain the balls within said loaded ball rolling groove.