Ultra-precision machine tool

An ultra-precision machine tool, which is provided with:

• a base (1),
• an X axis slider (3) provided movably in X direction horizontally on said base,
• a pair of X axis guide members (31,31) which are disposed at positions symmetric about the center of mass of said X axis slider so as to movably guide said X axis slider in X direction,
• a pair of X axis linear motors (32,32) which are disposed at positions symmetric about the center of mass of said X axis slider so as to drive said X axis slider in X direction,
• a table (33) which is rotatably supported on said X axis slider and on which is mounted a workpiece,
• a pair of Y axis sliders (4,4) which are disposed on said base on both sides of said X axis slider for X direction respectively so that said X axis slider is interposed therebetween and are provided movably in horizontal Y direction perpendicular to X direction,
• a pair of Y axis guide members (41,41) which are disposed on said base on both sides of said X axis slider for X direction respectively so as to movably guide said Y axis sliders in Y direction respectively,
• a pair of Y axis linear motors (42,42) which are disposed on said base on both sides of said X axis slider for X direction and at positions symmetric about the center of mass of the combination of said Y axis sliders so as to drive said Y axis sliders in Y direction,
• a pair of Z axis sliders (5,5) which are provided movably in Z direction perpendicular to X and Y directions on said pair of Y axis sliders respectively,
• two pairs of Z axis guide members (51,51) of which each pair of Z axis guide members are disposed at positions symmetric about the center of mass of each of said Z axis sliders on each of said Y axis sliders so as to movably guide said pair of Z axis sliders in Z direction respectively,
• two pairs of Z axis linear motors (52,52) of which each pair of Z axis linear motors are disposed at positions symmetric about the center of mass of each of said Z axis sliders on each of said Y axis sliders so as to drive said pair of Z axis sliders in Z direction,
• a spindle head supporting beam (6) in which both ends for X direction are rotatably supported on said Z axis sliders respectively so as to be capable of indexing rotationally about A axis parallel with X axis and
• a spindle head (61) which is secured to said spindle head supporting beam at the central position thereof and has a spindle for holding a tool.