Abstract: A backlash eliminator capable of eliminating backlash with a low loss while decreasing a backlash eliminating force to curtail friction and heat generation is provided.

Abstract: There is provided a built-in type index table in which a power transmitting means scarcely has backlash and, at the same time, the space and cost can be saved. The index table includes a rotary table for setting a workpiece for a machine tool; a rotary table shaft fixedly provided on the rotary table; a driving motor mechanism, which is a driving source; and a planetary roller speed-reduction mechanism having a sun roller, which is a motor output shaft of the driving motor mechanism, a ring fixed to the speed-reduction mechanism, a plurality of planetary rollers arranged at equal angular intervals between the sun roller and the ring in a pressurized state, and a planetary roller harness that fixedly supports a plurality of planetary roller shafts pivotally supporting the planetary rollers in a rotatable manner and is fixedly provided coaxially with the rotary table shaft.

Abstract: A gear grinding machine comprises: a moving mechanism rotatably mounted with a threaded grinding wheel, and arranged to move the threaded grinding wheel along directions of X, Z, and Y, and to turn the threaded grinding wheel in a Y-Z plane; an NC device for controlling the position of the threaded grinding wheel; and a rotary dressing device having a dressing tool which contacts the flanks of the threads of the threaded grinding wheel, while rotationally driven, to perform dressing. The NC device numerically controls the moving mechanism so as to adjust the positions in the directions of X and Z, and the turning position in the Y-Z plane of the threaded grinding wheel, while keeping contact of the dressing tool with the flanks of the threads of the threaded grinding wheel, in order to modify the wheel pressure angle of the threaded grinding wheel.

Abstract: A gear grinding machine comprises: a moving mechanism rotatably mounted with a threaded grinding wheel, and arranged to move the threaded grinding wheel along directions of X, Z, and Y, and to turn the threaded grinding wheel in a Y-Z plane; an NC device for controlling the position of the threaded grinding wheel; and a rotary dressing device having a dressing tool which contacts the flanks of the threads of the threaded grinding wheel, while rotationally driven, to perform dressing, and wherein the NC device numerically controls the moving mechanism so as to adjust the positions in the directions of X and Z, and the turning position in the Y-Z plane of the threaded grinding wheel, while keeping contact of the dressing tool with the flanks of the threads of the threaded grinding wheel, in order to modify the wheel pressure angle of the threaded grinding wheel.