Okuma Corporation

Yoshiichi Ichikawa

Yasushi Fukaya

Takashi Nishimoto

Yuji Naganawa

Mamoru Yamashita

Kazuhisa Niwa

A tailstock control device includes a tailstock parameter setting unit that receives, in advance, setting of tailstock acceleration time ta, tailstock movement velocity V, drive torque measuring period t, and number n of drive torque measurements; a calculating unit that calculates acceleration zone distance La from the acceleration time ta and the movement velocity V; a calculating unit that calculates constant velocity zone distance Lb from the movement velocity V, the measuring period t, and the number n of measurements; a drive torque detecting unit that detects servo motor drive torque; and a control unit that sets La+Lb as drive torque measuring distance Lt and calculates servo motor drive torque limit value &#x3c4;c from drive torque T detected by the drive torque detecting unit when the tailstock is moved over La+Lb and also from a servo motor torque command value &#x3c4;a required for supporting a workpiece.

Tailstock control device

A tailstock control device supports an object to be machined by driving and controlling a servo motor which drives a driving system of a tailstock having a spring member in forward and backward directions, to cause a tailstock center connected to the tailstock to contact a center hole of the object to be machined. The tailstock control device comprises a limit torque value calculating unit which calculates, as a limit torque value (Tm), a drive torque value of the servo motor necessary for supporting the object to be machined, and a servo control unit which drives and controls the servo motor to attempt to move the tailstock at a tailstock movement velocity (Vs) which is set in advance, until an output torque value (Tr) of the servo motor reaches the limit torque value (Tm). The limit torque value (Tm) is calculated by subtracting, from the support thrust (Fa) necessary for supporting the object to be machined, an excessive thrust Fs which is calculated based on the tailstock movement velocity (Vs).

When causing manual movement of a moving section of a machine tool, shape data of the moving section is made to move in a movement direction that has been input manually, and it is confirmed whether there is no interference with shape data of a surrounding interfering object. If interference occurs, a position returned a specified distance from the position where interference occurs is made a stop position, the moving section is moved to this stop position, and stopped at that position.

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Aichi, Japan

Yoshiichi Ichikawa