Abstract: A machine tool includes a rotary table to which a workpiece is mounted, a brake, a displays, a memory configured to store a table in which values of a first coefficient correspond to different sizes of a disturbance torque, and values of a second coefficient correspond to different sizes of inertia of the workpiece. The controller is configured to calculate a size of the disturbance torque, find a first coefficient corresponding to the calculated size of the disturbance torque and the table, find a second coefficient corresponding to the size of the inertia of the workpiece and the table, accumulate the found values of the first and second coefficients, and cause the display to generate an indicator of necessity of a replacement of the brake in response to that the accumulated values of the first and second coefficients reaches a predetermined value.

Abstract: A machine tool with a rotary table includes a disturbance torque calculation unit configured to calculate a disturbance torque imposed on the brake while the rotary table is retained by the brake, a first coefficient storing unit for storing a first coefficient corresponding to a disturbance torque, an accumulation unit configured to, when the disturbance torque is imposed on the brake, find a first coefficient corresponding to the disturbance torque and accumulate a value of the first coefficient, and, an annunciation unit configured to annunciate necessity of a brake replacement when the value of the first coefficient accumulated reaches a predetermined value.

Abstract: A corrected rotation amount, based on conversion to a rotation amount at a reference rotational speed, is obtained by multiplying a command speed read in each period by a period time and a coefficient value corresponding to the rotational speed. An integrated corrected rotation amount is obtained by integrating the corrected rotation amount. If this integrated corrected rotation amount exceeds a life limit value, the life of a bearing is determined to be exhausted.

Abstract: A rotation drive device that rotates a jig plate on which a workpiece is set and a rotating shaft supporting device that supports the jig plate are disposed such as to oppose each other with the jig plate interposed therebetween. The rotation drive device and the rotating shaft supporting device are placed on a base plate. A spacer is inserted between the rotation drive device or the rotating shaft supporting device and the base plate, thereby making equal a center height of a rotating axis of the rotation drive device and a center height of a rotating axis of the rotating shaft supporting device.

Abstract: A fan having a function for detecting a fault such as a breakage or a loss of a rotating part of the fan as well as reduction in the rotational speed of the fan, the function being not affected by an operating condition of the fan. The fan includes a stationary part, a rotating part rotatably attached to the stationary part, a first electric circuit arranged on the rotating part, a second electric circuit arranged on the stationary part, the second electric circuit being electromagnetically connected to the first circuit, and a fault detecting circuit electrically connected to the second electric circuit, for detecting a fault of the rotating part.

Abstract: A control unit for a machine tool at least one vibration detection device attached to a main shaft portion of a machine tool or a movable body; a storage device for storing a vibration signal detected by the vibration detection device being related to operation information of the machine tool; a collision judgment device for judging that a collision has occurred; and an output device for outputting the vibration signal at the time of judging the occurring of the collision. By the above constitution, the control unit is capable of grasping a specific circumstance of collision and quickly determining a cause of collision.

Abstract: A numeric control device with a simple structure of a machine tool, capable of detecting a defect of a spindle or a spindle motor of the machine tool and automatically informing an operator of the defect. A numeric control device has a first storing part, a calculating part and a judging part. The first storing part stores master vibration data of the spindle or the spindle motor, the master vibration data being prepared by associating data of the vibration outputted from a vibration sensor arranged on the spindle or the spindle motor with an operation pattern for detecting the defect of the spindle or the spindle motor. When a difference value between the master vibration data and newly obtained data exceeds a predetermined reference value, the judging part determines that the new data is abnormal.

Abstract: A control unit (10) for a machine tool comprises: at least one vibration detection means (31 to 33) attached to a main shaft portion (30) of a machine tool or a movable body moving relative to the main shaft portion (30), for example, attached to a holding table for a workpiece; a storage means (11) for storing a vibration signal detected by the vibration detection means being related to operation information of the machine tool; a collision judgment means (12) for judging that a collision has occurred in the case where the vibration signal stored in the storage means exceeds a previously determined threshold value when comparing the vibration signal with the threshold value; and an output means (13) for outputting the vibration signal at the time of judging the occurring of the collision and also outputting the operation information stored in the storage means related to the vibration signal in the case where the collision judgment means judges that the collision has occurred.

Abstract: A method of insulating the proximal portions of the coil edges of the stator. The insulation sheet has a folding portion for folding one or more coils of the same phase and two insertion portions extending from the folding portion so that distal ends are positioned away from a centerline of the folding portion. One or more coils of the same phase are folded by the folding portion and the two inserting portions are inserted into the slot or slots from which the one or more coils project. The inserting portions are drawn from inside of the stator core so that the folding portion spreads to fold the proximal portions of the coils. The inserting portions are securely held between the wall of the slots and the coils to prevent the insulation sheet from displacement, inclination and slip off to securely insulate the coils of different phases.

Abstract: An electric motor capable of ensuring insulation of proximal portions of coil edges of a stator projecting from end of a stator core, and a method of insulating the proximal portions of the coil edges of the stator. The insulation sheet has a folding portion for folding one or more coils of the same phase and two insertion portions extending from the folding portion so that distal ends are positioned away from a centerline of the folding portion. One or more coils of the same phase are folded by the folding portion and the two inserting portions are inserted into the slot or slots from which the one or more coils project. The inserting portions are drawn from inside of the stator core so that the folding portion spreads to fold the proximal portions of the coils. The inserting portions are securely held between the wall of the slots and the coils to prevent the insulation sheet from displacement, inclination and slip off to securely insulate the coils of different phases.

Abstract: A fan having a function for detecting a fault such as a breakage or a loss of a rotating part of the fan as well as reduction in the rotational speed of the fan, the function being not affected by an operating condition of the fan. The fan includes a stationary part, a rotating part rotatably attached to the stationary part, a first electric circuit arranged on the rotating part, a second electric circuit arranged on the stationary part, the second electric circuit being electromagnetically connected to the first circuit, and a fault detecting circuit electrically connected to the second electric circuit, for detecting a fault of the rotating part.

Abstract: An impact detection device includes a vibration sensor attached to an object, a receiving unit for receiving the output signal from the vibration sensor, a peak hold circuit for holding the largest value in a continuous output signal received by the receiving unit as a peak value, and an output unit for outputting the peak value held by the peak hold circuit as data for judging collision of the object.

Abstract: An air-cooled motor has a motor body in which a through hole is formed in a rotary shaft, a supply section for supplying a fluid to the through hole, a cylindrical member surrounding the supply section, and a cooling fan provided on the side opposite the motor body with respect to the cylindrical member. A window is provided in the cylindrical member or at least a part of the cylindrical member is made of a transparent material so that the supply section can be visually observed.

Abstract: An electric motor capable of ensuring insulation of proximal portions of coil edges of a stator projecting from end of a stator core, and a method of insulating the proximal portions of the coil edges of the stator. The insulation sheet has a folding portion for folding one or more coils of the same phase and two insertion portions extending from the folding portion so that distal ends are positioned away from a centerline of the folding portion. One or more coils of the same phase are folded by the folding portion and the two inserting portions are inserted into the slot or slots from which the one or more coils project. The inserting portions are drawn from inside of the stator core so that the folding portion spreads to fold the proximal portions of the coils. The inserting portions are securely held between the wall of the slots and the coils to prevent the insulation sheet from displacement, inclination and slip off to securely insulate the coils of different phases.

Abstract: An electric motor capable of ensuring insulation of proximal portions of coil edges of a stator projecting from end of a stator core, and a method of insulating the proximal portions of the coil edges of the stator. The insulation sheet has a folding portion for folding one or more coils of the same phase and two insertion portions extending from the folding portion so that distal ends are positioned away from a centerline of the folding portion. One or more coils of the same phase are folded by the folding portion and the two inserting portions are inserted into the slot or slots from which the one or more coils project. The inserting portions are drawn from inside of the stator core so that the folding portion spreads to fold the proximal portions of the coils. The inserting portions are securely held between the wall of the slots and the coils to prevent the insulation sheet from displacement, inclination and slip off to securely insulate the coils of different phases.

Abstract: An air-cooled motor has a motor body in which a through hole is formed in a rotary shaft, a supply section for supplying a fluid to the through hole, a cylindrical member surrounding the supply section, and a cooling fan provided on the side opposite the motor body with respect to the cylindrical member. A window is provided in the cylindrical member or at least a part of the cylindrical member is made of a transparent material so that the supply section can be visually observed.

Abstract: Wedge guides 12 for holding a wedge 11 are mounted onto a base 10, and a stripper 15 is fixed to the other end of the wedge guide 12. A blade holder 13 including a plurality of blades 16 vertically installed is held in such a manner as to be freely advanceable and retractable in an up-and-down direction. A coil 30 wound is inserted between the blades 16, and alignment tool 7 is inserted at the tip ends of the blades. A stator iron core 40 is inserted into the alignment tool 7, and the stator iron core 40 is moved until the tip ends of the blades 16 penetrate the stator iron core 40. Thereafter, the stator iron core 40 and a connecting rod 19, the other end of which being connected to the blade holder 13, are pushed by a stator pusher 50, whereby the blade holder 13 is also caused to move together with the stator iron core 40 to insert the coil 30 into grooves in the stator iron core 40.

Abstract: An induction motor capable of obtaining a high power characteristic in a wide range without producing induced voltage. A winding for each phase is composed of a plurality of winding components having the same number of turns. When high torque is needed with low speed rotation, a Y-connection in which winding components for each phase are connected in series is formed as shown in FIG. 2a. For medium low speed rotation, a &Dgr;-connection in which winding components for each phase are connected in series is formed as shown in FIG. 2b. For medium high speed rotation, a Y-connection in which winding components for each phase are connected in parallel is formed as shown in FIG. 2c. For high speed rotation, a &agr;-connection in which winding components for each phase are connected in parallel is formed as shown in FIG. 2d. Using the entire winding for each phase, the number of turns is decreased stage by stage to switch from low speed rotation to high speed rotation.

Abstract: Wedge guides 12 for holding a wedge 11 are mounted onto a base 10, and a stripper 15 is fixed to the other end of the wedge guide 12. A blade holder 13 including a plurality of blades 16 vertically installed is held in such a manner as to be freely advanceable and retractable in an up-and-down direction. A coil 30 wound is inserted between the blades 16, and alignment tool 7 is inserted at the tip ends of the blades. A stator iron core 40 is inserted into the alignment tool 7, and the stator iron core 40 is moved until the tip ends of the blades 16 penetrate the stator iron core 40. Thereafter, the stator iron core 40 and a connecting rod 19, the other end of which being connected to the blade holder 13, are pushed by a stator pusher 50, whereby the blade holder 13 is also caused to move together with the stator iron core 40 to insert the coil 30 into grooves in the stator iron core 40.

Abstract: A reactor (32) and a switch (35) are interposed in parallel between U-phase, V-phase and W-phase on a power source side (31) and U, V and W terminals on a motor side (33). A changeover switch )37) is interposed between Z, X and Y terminals on the motor side (33) and the U, V and W terminals on the motor side (33). When the switch (35) is set to OFF, the changeover switch (37) is set to ON, and the switch (35) is set up so as to interconnect Z, X and Y terminals, windings of the motor are set up in the form of Y-connection, so that the motor and a power source are connected directly to each other. On the other hand, when the changeover switch (37) is switched over to OFF, and the switch (35) is set up so as to interconnect Z, X and Y terminals to the U, V and W terminals, the windings of the motor are set up in the form of &Dgr;-connection, so that the motor and the power source are connected together through the reactor (32).