Motor-driven working spindle for a machine tool
A motor-driven working spindle for a machine tool has a casing in which a shaft is mounted for rotation. The shaft has a receptacle for a tool arranged at its front end. A spindle rotary drive is provided in the casing. Furthermore, a spindle advancing drive coupled with the shaft is provided in the casing.
1. A motor-driven working spindle for a machine tool comprising:
a casing with a central longitudinal axis extending from a front of the spindle to the rear of the spindle;
a shaft mounted for rotation in the casing;
a receptacle arranged on a front end of the shaft, in which receptacle, by means of a clamping device, a machining tool is releasably clampable;
a pull rod mounted for displacement in the shaft, whereby the clamping device may be actuated by the pull rod;
a spindle advancing drive coupled to the shaft and positioned in the casing; wherein the shaft is mounted in the casing for displacement by the spindle advancing drive through a working stroke in the direction of the central longitudinal axis;
an end wall positioned in the casing, wherein the pull rod may be seated against the end wall by moving the pull rod in the direction of the central longitudinal axis; and wherein the shaft is displaceable, by means of the spindle advancing drive, relative to the pull rod that is seated against the end wall, for releasing the clamping device;
an electromotive spindle rotary drive coupled to the shaft and arranged in the casing, the spindle rotary drive comprising;
a rotary drive stator and a rotary drive rotor,
wherein the rotary drive stator surrounds the shaft and is mounted in the casing;
and wherein the rotary drive rotor is fastened to the shaft; and,
wherein the spindle advancing drive is to the rear of the rotary drive, and the end wall is to the rear of the spindle advancing drive.
2. A working spindle according to claim 1 further comprising:
the spindle advancing drive comprising a spindle advancing stator mounted in the casing and a spindle advancing rotor;
a threaded nut coupled to the spindle advancing rotor, the threaded nut being rotationally mounted in the casing and non-displaceable in the direction of the central longitudinal axis; and
a threaded sleeve coupled to the threaded nut, the threaded sleeve being axially displaceable but rotationally fixed on the shaft.
3. A working spindle according to claim 2 further comprising: a torque motor comprising the spindle advancing drive.
4. A working spindle according to claim 1 further comprising:
a stack of rotor laminations with a length a in the direction of the central longitudinal axis comprising the rotary drive rotor of the spindle rotary drive; and
a stack of stator laminations with a length b comprising the rotary drive stator of the spindle rotary drive; wherein a is substantially greater than b.
5. A working spindle according to claim 4 ,
wherein a maximum value of the working stroke of the shaft is approximately equal to a−b.
6. A working spindle according to claim 1 further comprising:
a sliding sleeve mounted in the casing,
wherein the shaft is mounted in the casing by means of the sliding sleeve.
7. A working spindle according to claim 1 further comprising:
a spring positioned between the shaft and the pull rod, the spring being arranged for clamping the clamping device.
8. A working spindle according to claim 1 further comprising:
a first measuring device for measuring the axial position of the shaft.
9. A working spindle according to claim 1 further comprising:
a second measuring device for measuring the rotary position of the shaft.