Device for determining a rotational position when changing tools and method for determining a rotational position when changing tools

摘要

A device (40) for determining a rotational position during tool change for use with a machine tool (10), the machine tool comprising: a rotatable turret head (24) comprising a plurality of gripping devices (24a) which are arranged along a circumferential direction thereof and each are able to hold a tool (14) to be attached to an attachment hole (12a) of a spindle (12) by means of a tool holder (14a); and a rotary motor (36) configured to rotate the turret (24), wherein the device for determining a rotational position when changing tools determines a rotational position when changing tools of the turret (24) when the machine tool (10) holds the tool (14 ) between the gripping device (24a) and the spindle (12) to attach the tool (14) to the spindle (12) or to remove the tool (14) therefrom, the device (40) comprising: a unit (46) for detecting a load torque configured to detect a load torque on the rotary motor (36); a unit (44) for detecting a rotational position configured to detect a rotational position of the rotary motor (36); a turret rotation controller ( 50) configured to control the rotary motor (36) to rotate the turret (24) clockwise and counterclockwise in a state in which the tool holder (14a) of the tool (14), the dur ch gripping a specific gripping device (24a) of the plurality of gripping devices (24a) is inserted into the attachment hole (12a) of the spindle (12); anda tool changing rotational position determining unit (52) configured to change the tool changing rotational position of the turret (24) when the tool (14) to be attached to and detached from the spindle (12) is between the specific Gripping device (24a) and the spindle (12) is transmitted based on the load moments detected by the unit (46) for detecting a load moment, and on the rotational positions detected by the unit (44) for detecting a rotational position when the turret (24) is rotated clockwise and counterclockwise.