Abstract: There is provided a method of compensating a command value for rotation angle capable of precisely compensating a command value for rotation angle even when conditions at detection differ to thereby make error patterns different in the case where a tooth-to-tooth period error pattern in an arbitrary tooth period is used for all the tooth periods to correct a command value for rotation angle. A forward direction tooth-to-tooth period error pattern being an error pattern of detected rotation angles at forward rotation and the actual rotation angles and a backward direction tooth-to-tooth period error pattern being an error pattern at backward rotation are found, and the command value for rotation angle is corrected based on the error pattern at the time of forward rotation, and the command value for rotation angle is corrected based on the error pattern at the time of backward rotation.

Abstract: A machine tool having a turning function and a milling function includes a spindle, a spindle housing supporting the spindle in a rotatable manner, a main clamp provided at the spindle, an auxiliary clamp provided at the spindle housing, and a double arm with a first gripper and a second gripper. The auxiliary clamp clamps a tool holder together with the main clamp during fixing a fixed tool. The double arm exchanges a tool holder grasped at the first gripper for another tool holder grasped at the second gripper by rotating and sliding movements. The auxiliary clamp is arranged at a position not interfering with the double arm that moves during exchanging tool holders. By such a configuration, a machine tool achieving a clamping force sufficient to withstand the load during a turning process, and that allows tool exchange in a short period of time, and a tool holder employed in such a machine tool, can be provided.

Abstract: There is provided a method of compensating a command value for rotation angle capable of precisely compensating a command value for rotation angle even when conditions at detection differ to thereby make error patterns different in the case where a tooth-to-tooth period error pattern in an arbitrary tooth period is used for all the tooth periods to correct a command value for rotation angle.

Abstract: A machine tool having a turning function and a milling function includes a spindle, a spindle housing supporting the spindle in a rotatable manner, a main clamp provided at the spindle, an auxiliary clamp provided at the spindle housing, and a double arm with a first gripper and a second gripper. The auxiliary clamp clamps a tool holder together with the main clamp during fixing a fixed tool. The double arm exchanges a tool holder grasped at the first gripper for another tool holder grasped at the second gripper by rotating and sliding movements. The auxiliary clamp is arranged at a position not interfering with the double arm that moves during exchanging tool holders. By such a configuration, a machine tool achieving a clamping force sufficient to withstand the load during a turning process, and that allows tool exchange in a short period of time, and a tool holder employed in such a machine tool, can be provided.

Abstract: A machine tool having a turning function and a milling function includes a spindle, a spindle housing supporting the spindle in a rotatable manner, a main clamp provided at the spindle, an auxiliary clamp provided at the spindle housing, and a double arm with a first gripper and a second gripper. The auxiliary clamp clamps a tool holder together with the main clamp during fixing a fixed tool. The double arm exchanges a tool holder grasped at the first gripper for another tool holder grasped at the second gripper by rotating and sliding movements. The auxiliary clamp is arranged at a position not interfering with the double arm that moves during exchanging tool holders. By such a configuration, a machine tool achieving a clamping force sufficient to withstand the load during a turning process, and that allows tool exchange in a short period of time, and a tool holder employed in such a machine tool, can be provided.

Abstract: To provide a machine tool capable of preventing even chips in a powder form and coolant from leaking to a feed mechanism side. A slide plate 12 is provided to cover a feed mechanism 16. The slide plate 12 is fixed to a second headstock 6 to move in an axial direction together with the second headstock 6. Between the slide plate 12 and a bed side member, a seal portion 31 is provided. The seal portion 31 has a first slide contact member 20 provided on the slide plate 12 and a second slide contact member 18b which is provided on the bed side member and in slide contact with the first slide contact member 20, and the first and second slide contact members 20 and 18b relatively slide while being in contact with each other.

Abstract: A machine tool having a turning function and a milling function includes a spindle, a spindle housing supporting the spindle in a rotatable manner, a main clamp provided at the spindle, an auxiliary clamp provided at the spindle housing, and a double arm with a first gripper and a second gripper. The auxiliary clamp clamps a tool holder together with the main clamp during fixing a fixed tool. The double arm exchanges a tool holder grasped at the first gripper for another tool holder grasped at the second gripper by rotating and sliding movements. The auxiliary clamp is arranged at a position not interfering with the double arm that moves during exchanging tool holders. By such a configuration, a machine tool achieving a clamping force sufficient to withstand the load during a turning process, and that allows tool exchange in a short period of time, and a tool holder employed in such a machine tool, can be provided.

Abstract: To provide a machine tool capable of preventing even chips in a powder form and coolant from leaking to a feed mechanism side. A slide plate 12 is provided to cover a feed mechanism 16. The slide plate 12 is fixed to a second headstock 6 to move in an axial direction together with the second headstock 6. Between the slide plate 12 and a bed side member, a seal portion 31 is provided. The seal portion 31 has a first slide contact member 20 provided on the slide plate 12 and a second slide contact member 18b which is provided on the bed side member and in slide contact with the first slide contact member 20, and the first and second slide contact members 20 and 18b relatively slide while being in contact with each other.