Abstract: It is an object of the present invention to provide a bed of a machine tool to be stably leveled and supported by three support points and to reduce the strain of the bed of which structure is simplified. The bed of the machine tool according to the present invention comprises three props and a ceiling 18. The props are arranged as a triangle. The ceiling is put on the props and supports at least one tool box and work saddle. In the triangle in view of horizontal plane, there exists center of gravity of the whole machine tool.

Abstract: It is an object of the present invention to provide a bed of a machine tool to be stably leveled and supported by three support points and to reduce the strain of the bed of which structure is simplified.

Abstract: A grinding wheel is for use in a grinding machine, and is attached on a wheel spindle of the grinding machine for simultaneously grinding at least two parts of a workpiece. The grinding wheel includes at least two wheel cores. Each of wheel cores has a disk-like shape. An abrasive layer is disposed on a circumferential surface of each of the wheel cores. A spacer portion is inseparably fixed on at least one of the wheel cores for keeping a space between the abrasive layers of the wheel cores. And a first labyrinth portion located on one of side surfaces of one of the wheel cores for forming a labyrinth seal with a second labyrinth portion arranged on the grinding machine. The number of separable parts of the grinding wheel are extremely decreased in consideration of imbalance of every part. The spacer portion is integral with at least one of the wheel cores.

Abstract: A wheel-head feed mechanism for a grinder comprising a base and a wheel head which is guided by a linear guide section provided on the base and rotatably supports a grinding wheel via a wheel spindle driven by a motor. The wheel-head feed mechanism includes feed screw mechanism composed of a screw shaft and a nut unit engaged with the screw shaft, the feed screw mechanism advancing and retracting the wheel head with respect to a workpiece, and servomotor for rotating one of the screw shaft and the nut unit. The screw shaft is offset from the linear guide section toward the wheel spindle. The nut unit includes a radial hydrostatic bearing section for supporting the root of a male thread of the screw shaft in the radial direction of the screw shaft by hydrostatic pressure, as well as a thrust hydrostatic bearing section for supporting the flanks of the male thread of the screw shaft in the axial direction of the screw shaft by hydrostatic pressure.