Abstract: A numerical control system diagnoses and maintains a numerical control machine tool by measuring backlash and downloading a backlash correction value to the numerical control machine tool. The system includes a host computer device that downloads a monitor management program to a numerical controller of the numerical control machine tool, collects numerical control information input/output between the numerical controller and a servomotor, analyzes the numerical control information, and diagnoses the numerical control machine tool.

Abstract: A system determining whether the feed shafts are normal or abnormal, the system including: a command generation unit that moves the feed shafts in a forward direction at a predetermined speed from a lower limit value to an upper limit value of a range of feeding movement by the numerical controller; and a feed shaft abnormality determination unit that monitors a drive torque command during the movement of the feed shafts in the forward direction by the command generation unit, compares a monitoring result during the movement in the forward direction with a normal value of the drive torque command, determines that abnormality occurs when the drive torque command deviates from the normal value, and outputs the determination result.

Abstract: A tool holder attachment structure includes a spindle and a tool holder. The spindle has a tip end face and a tapered hole. The tool holder has a tapered shank portion and a flange end face. In a clamped state, there is a clearance of a predetermined size between the flange end face of the tool holder and the tip end face of the spindle. As the spindle is rotated, the tapered hole of the spindle is slightly expanded by a centrifugal force caused by rotation of the spindle, and the presence of this clearance allows the tapered shank portion to be further drawn into the tapered hole so that the flange end face of the tool holder closely contacts the tip end face of the spindle, and the tapered shank portion is closely fitted in the tapered hole, whereby two-face restraint is implemented.

Abstract: In a shank portion of an end mill which is chucked by a tool holder, flat surfaces are formed at a plurality of circumferential positions in the outer periphery of the shank portion so that the flat surfaces abut on side lock bolts attached to a body of the tool holder.

Abstract: In a shank portion of an end mill which is chucked by a tool holder, flat surfaces are formed at a plurality of circumferential positions in the outer periphery of the shank portion so that the flat surfaces abut on side lock bolts attached to a body of the tool holder.

Abstract: A tool holder includes a drawing screw and a stopper member. The drawing screw is positioned in an intermediate hole. A rear end face of a head of the drawing screw faces a boundary wall surface, and a top end of a shaft of the drawing screw is screwed in a rear end of a collet. The stopper member is positioned in an annular space between an outer peripheral surface of the shaft of the drawing screw and an inner peripheral surface of the intermediate hole. The stopper member faces a front end face of the head of the drawing screw, and limits movement of the head toward a top end of the tool holder. The drawing screw and the stopper member are inserted and assembled from a top end opening of a collet holding hole.

Abstract: A tool holder attachment structure includes a spindle and a tool holder. The spindle has a tip end face and a tapered hole. The tool holder has a tapered shank portion and a flange end face. In a clamped state, there is a clearance of a predetermined size between the flange end face of the tool holder and the tip end face of the spindle. As the spindle is rotated, the tapered hole of the spindle is slightly expanded by a centrifugal force caused by rotation of the spindle, and the presence of this clearance allows the tapered shank portion to be further drawn into the tapered hole so that the flange end face of the tool holder closely contacts the tip end face of the spindle, and the tapered shank portion is closely fitted in the tapered hole, whereby two-face restraint is implemented.

Abstract: In a shank portion of an end mill which is chucked by a tool holder, flat surfaces are formed at a plurality of circumferential positions in the outer periphery of the shank portion so that the flat surfaces abut on side lock bolts attached to a body of the tool holder.

Abstract: A rotary table includes a brake mechanism capable of providing a large and sufficient brake force. The brake mechanism includes an inner peripheral surface and outer peripheral surface of a sleeve formed coaxially with an axis of a rotatable table, an outer stationary portion provided to a stationary member rotatably supporting the rotatable table and defining an outer hydraulic chamber, and an inner stationary portion provided to the stationary member, arranged radially inward from the outer stationary portion and defining an inner hydraulic chamber. The outer stationary portion is elastically deformed in a radial direction by expansion of the outer hydraulic chamber to push the outer peripheral surface of the sleeve formed on the rotatable table, while the inner stationary portion is elastically deformed in a radial direction by expansion of the inner hydraulic chamber to push the inner peripheral surface of the sleeve formed on the rotatable table.

Abstract: A tool holder includes: a collet chuck main body having a tapered hole formed in its tip end portion so as to be tapered toward an axial rear end; a tapered collet having a tool insertion hole that extends in an axial direction, a main tapered surface that fits in the tapered hole, and a tip end tapered surface positioned on an axial tip end side of the main tapered surface, and tapered toward an axial tip end; a cylindrical lock nut having internal threads that are screwed on external threads formed on an outer periphery of the tip end portion of the collet chuck main body, for reducing a diameter of the tool insertion hole by pressing the tapered collet into the tapered hole; a tip end tapered member having a tapered abutting surface that fits on the tip end tapered surface, the tip end tapered member being pressed toward the axial rear end by the lock nut; and a plain bearing positioned in a plane perpendicular to a direction in which the tip end tapered member is pressed by the lock nut, the plain bearing

Abstract: A rotary table assembly is configured to prevent torsional deformation of a sealing member on an outer peripheral surface of a rotary joint. The rotary joint has a distributor and a center shaft, which includes two hollow cylindrical center shafts respectively inserted into a through hole from opposite front and back surface sides of a rotatable table. The sealing member makes contact with the outer peripheral surface of the hollow cylindrical center shaft positioned near the front surface of the rotatable table. The distributor has a top region that is successively inserted from the back surface side of the rotatable table into the two hollow cylindrical center shafts, and a basal portion secured to a frame.

Abstract: A rotary table includes a brake mechanism capable of providing a large and sufficient brake force. The brake mechanism includes an inner peripheral surface and outer peripheral surface of a sleeve formed coaxially with an axis of a rotatable table, an outer stationary portion provided to a stationary member rotatably supporting the rotatable table and defining an outer hydraulic chamber, and an inner stationary portion provided to the stationary member, arranged radially inward from the outer stationary portion and defining an inner hydraulic chamber. The outer stationary portion is elastically deformed in a radial direction by expansion of the outer hydraulic chamber to push the outer peripheral surface of the sleeve formed on the rotatable table, while the inner stationary portion is elastically deformed in a radial direction by expansion of the inner hydraulic chamber to push the inner peripheral surface of the sleeve formed on the rotatable table.

Abstract: A tool holder, which is inserted into a center-through-coolant spindle and employs a side-lock type chuck structure, can reliably prevent leakage of cutting liquid from a bolt hole for a side-lock bolt. The tool holder includes a side-lock bolt and an annular seal member. The side-lock bolt is inserted into a through hole extending from an outer peripheral surface to an inner peripheral surface of a tool attachment portion, threadedly engaged with an internal thread formed in the through hole, and secures a shank of a tool to a tool-holding bore. The seal member seals between the through hole and side-lock bolt.

Abstract: A rotary table assembly is configured to prevent torsional deformation of a sealing member on an outer peripheral surface of a rotary joint. The rotary joint has a distributor and a center shaft, which includes two hollow cylindrical center shafts respectively inserted into a through hole from opposite front and back surface sides of a rotatable table. The sealing member makes contact with the outer peripheral surface of the hollow cylindrical center shaft positioned near the front surface of the rotatable table. The distributor has a top region that is successively inserted from the back surface side of the rotatable table into the two hollow cylindrical center shafts, and a basal portion secured to a frame.

Abstract: A tool holder includes a drawing screw and a stopper member. The drawing screw is positioned in an intermediate hole. A rear end face of a head of the drawing screw faces a boundary wall surface, and a top end of a shaft of the drawing screw is screwed in a rear end of a collet. The stopper member is positioned in an annular space between an outer peripheral surface of the shaft of the drawing screw and an inner peripheral surface of the intermediate hole. The stopper member faces a front end face of the head of the drawing screw, and limits movement of the head toward a top end of the tool holder. The drawing screw and the stopper member are inserted and assembled from a top end opening of a collet holding hole.

Abstract: A tool holder includes: a collet chuck main body having a tapered hole formed in its tip end portion so as to be tapered toward an axial rear end; a tapered collet having a tool insertion hole that extends in an axial direction, a main tapered surface that fits in the tapered hole, and a tip end tapered surface positioned on an axial tip end side of the main tapered surface, and tapered toward an axial tip end; a cylindrical lock nut having internal threads that are screwed on external threads formed on an outer periphery of the tip end portion of the collet chuck main body, for reducing a diameter of the tool insertion hole by pressing the tapered collet into the tapered hole; a tip end tapered member having a tapered abutting surface that fits on the tip end tapered surface, the tip end tapered member being pressed toward the axial rear end by the lock nut; and a plain bearing positioned in a plane perpendicular to a direction in which the tip end tapered member is pressed by the lock nut, the plain bearing