In a machine tool, when machining is in a steady zone, a rotation phase of a main spindle at the time of measurement in the N-th sampling is calculated, and the calculated rotation phase and the measurement value are recorded in a recording section so as to be associated with each other. The measurement and calculation of the rotation phase of the main spindle at the time of each measurement are continued for plural times of rotations of the main spindle, and thus the measurement values are obtained at various rotation phases, whereby change in drive force during one rotation of the main spindle is finally calculated.

In a machine tool, when machining is in a steady zone, a rotation phase of a main spindle at the time of measurement in the N-th sampling is calculated, and the calculated rotation phase and the measurement value are recorded in a recording section so as to be associated with each other. The measurement and calculation of the rotation phase of the main spindle at the time of each measurement are continued for plural times of rotations of the main spindle, and thus the measurement values are obtained at various rotation phases, whereby change in drive force during one rotation of the main spindle is finally calculated.

A spindle phase indexing device for a machine tool is equipped with a guide rail detachably or fixedly attached to a table, a phase indexing jig configured to travel on the guide rail and which includes a first fitting part, a cutting tool including a second fitting part configured to be fitted with the first fitting part, and a controller configured to store therein a phase of a spindle at a point in time when the first fitting part and the second fitting part are fitted together. The first fitting part and the second fitting part are formed such that rotation of the cutting tool is constrained when the first fitting part and the second fitting part are fitted together.

A spindle phase indexing device for a machine tool is equipped with a guide rail detachably or fixedly attached to a table, a phase indexing jig configured to travel on the guide rail and which includes a first fitting part, a cutting tool including a second fitting part configured to be fitted with the first fitting part, and a controller configured to store therein a phase of a spindle at a point in time when the first fitting part and the second fitting part are fitted together. The first fitting part and the second fitting part are formed such that rotation of the cutting tool is constrained when the first fitting part and the second fitting part are fitted together.

The invention relates to a machine for the gear cutting machining of workpieces, in particular a gear shaping machine, comprising a spindle for holding a machining tool, and a drive by means of which the spindle can be rotationally driven about its spindle axis, and further comprising an arrangement. When said arrangement is actuated, a spindle rotation caused by the drive changes the axial relative position with respect to the spindle axis.

The invention relates to a machine for the gear cutting machining of workpieces, in particular a gear shaping machine, comprising a spindle for holding a machining tool, and a drive by means of which the spindle can be rotationally driven about its spindle axis, and further comprising an arrangement. When said arrangement is actuated, a spindle rotation caused by the drive changes the axial relative position with respect to the spindle axis.

Spindle units are provided for machining devices, in particular for a lathing spindle unit, center drive assembly or milling spindle unit. The spindle unit comprises: a spindle shaft rotatably supported in a housing, a chucking device disposed at the spindle shaft for clamping a workpiece or a tool, a motor drive connected to the spindle shaft for driving the spindle shaft around a drive axis, a clamping device for clamping the spindle shaft at a freely selectable angular position around the drive axis, wherein the clamping device is disposed between the spindle shaft and a stationary part of the spindle unit, and an actuating device for actuating and/or releasing the clamping device. The clamping device can be axially actuated in the direction of the drive axis such that an axial or substantial axial clamping force acts in the direction of the drive axis with the clamping device being actuated.

Spindle units are provided for machining devices, in particular for a lathing spindle unit, center drive assembly or milling spindle unit. The spindle unit comprises: a spindle shaft rotatably supported in a housing, a chucking device disposed at the spindle shaft for clamping a workpiece or a tool, a motor drive connected to the spindle shaft for driving the spindle shaft around a drive axis, a clamping device for clamping the spindle shaft at a freely selectable angular position around the drive axis, wherein the clamping device is disposed between the spindle shaft and a stationary part of the spindle unit, and an actuating device for actuating and/or releasing the clamping device. The clamping device can be axially actuated in the direction of the drive axis such that an axial or substantial axial clamping force acts in the direction of the drive axis with the clamping device being actuated.

A cutting apparatus adapted for use in a machine tool. The cutting apparatus includes a mounting frame. A cutting unit is mounted rotatably in the mounting frame. A locking unit is connected to the mounting frame and the cutting unit, for restraining or permitting relative movement between the mounting frame and the cutting unit. A driving unit drives rotation of the cutting unit. A control unit controls the driving unit to drive rotation of the rotating shaft upon detecting that the relative movement between the mounting frame and the cutting unit is permitted. The control unit shuts off the driving unit upon detecting that the relative movement between the mounting frame and the cutting unit is restrained.

A cutting apparatus adapted for use in a machine tool. The cutting apparatus includes a mounting frame. A cutting unit is mounted rotatably in the mounting frame. A locking unit is connected to the mounting frame and the cutting unit, for restraining or permitting relative movement between the mounting frame and the cutting unit. A driving unit drives rotation of the cutting unit. A control unit controls the driving unit to drive rotation of the rotating shaft upon detecting that the relative movement between the mounting frame and the cutting unit is permitted. The control unit shuts off the driving unit upon detecting that the relative movement between the mounting frame and the cutting unit is restrained.