Abstract: A multi-function machine tool provided with a motor-driven spindle on which each of a plurality of sub-motor units having individual drive motors and tools, respectively, can be removably mounted to perform a plurality of machining operations in order to comply with a change in the machining conditions and a change in the material of workpieces to be machined. The drive motors of the sub-motor units exert different output performances, i.e., different rated rotating speeds and different output torques, and can be electrically connected to the electric powers lines and control signal lines provided for the spindle head.

Abstract: A terminal box for a motor is made of a thick plastic plate and includes a plurality of closed windows provided on the terminal box. Each of the closed windows is made of a thin plastic plate. The plurality of closed windows are each surrounded by a groove which is one of a plurality of concentric circular grooves. The terminal box is also provided with a plurality of radial linear grooves passing through a center of the concentric circular grooves to produce an open window for positioning a conduit therein when one of the plurality of closed windows is broken.

Abstract: A rotor 14 for a high speed induction type ac motor having a construction such that the rotor is provided with an iron core 20 provided, at the periphery thereof, with a plurality of through-bores 22 in which electro-conductive rods 24 made of aluminum rod members are forcibly inserted in a press-fitting manner so as to form opposite projections from the axial opposite ends of the iron core 20, electro-conductive end rings 26 connected to the projections of the electro-conductive rods 24, and slitted pins 30 press-fit in small blind bores 32 formed in the projections of the electro-conductive rods 24 to thereby fixedly attach the electro-conductive rings 26 to the opposite end faces of the iron core 20.

Abstract: A spindle motor for a machine tool is required to operate at a low rotational speed and to deliver a high output in a machining mode, and is required to operate at a high rotational speed and to deliver a high output in another machining mode. An AC motor employing a winding arrangement of the present invention meets those operating conditions for different machining modes, in that the coils (X1, X2; X1', X2') of each winding for a phase are divided into a plurality of sets of coils, and the plurality of sets of coils are held in a slot (SL). The connection of terminals (U1, U2; V1, V2; W1, W2) for phase dividing the coils into the sets is changed selectively by switching unit (SW, SW') such as an electromagnetic relay, to thereby supply power selectively to the coils for the output regulation.

Abstract: The stator of a built-in motor must be firmly and accurately mounted on the spindle head housing or the like of a machine tool. A stator core (10), i.e., a principal component of the stator is welded partially at the circumference (14) thereof, and then the circumference of the stator core (10) held by a mandrel is finished to an accurate outside diameter by grinding. The stator core (10) thus constructed is subjected to a deformation with a lapse of time after the mandrel has been removed. To solve this problem, each lamination (12) of the stator core (10) is coated with a thermosetting adhesive, to be thereby joined together, and each lamination (12) is provided with a plurality of pressed projections (22) to be joined together by weld portions (20) on the circumference of the stator core (10), or each lamination (12) is joined together by pressing a serrated bar (26) into a bore (24) thereof, without a pressed projection (22).

Abstract: The stator of a built-in motor must be firmly and accurately mounted on the spindle head housing or the like of a machine tool. A stator core (10), i.e., a principal component of the stator is welded partially at the circumference (14) thereof, and then the circumference of the stator core (10) held by a mandrel is finished to an accurate outside diameter by grinding. The stator core (10) thus constructed is subjected to a deformation with a lapse of time after the mandrel has been removed. To solve this problem, each lamination (12) of the stator core (10) is coated with a thermosetting adhesive, to be thereby joined together, and each lamination (12) is provided with a plurality of pressed projections (22) to be joined together by weld portions (20) on the circumference of the stator core (10), or each lamination (12) is joined together by pressing a serrated bar (26) into a bore (24) thereof, without a pressed projection (22).

Abstract: An ac spindle motor (10) for driving a spindle motor of a machine tool provided with a rotor (14) having an output shaft (12) connected to the spindle, and a stator (16) surrounding the rotor and having a laminated core (20) serving as a yoke, and stator winding assemblies of three phases (U-phase, V-phase, W-phase). The stator winding assembly of each phase (18u, 18v, 18w) has: windings (C.sub.2, C.sub.4) of a first group which are energized for a rotation of the spindle in both a low-speed range not higher than a given speed, and a high-speed range above the given speed; windings (C.sub.1, C.sub.3) of a second group energized only for a rotation of the spindle in the low-speed range; and electrical contact means (S1, S2, S3, S4) controlled so that the windings (C.sub.1, C.sub.2, C.sub.3, C.sub.4) of the first and second groups are energized to generate a first multipolar revolving magnetic field for the rotation of the spindle in the low-speed range, and so that only the windings (C.sub.2, C.sub.

Abstract: Low rotational speed characteristics of a three-phase induction motor driven by a PWM inverter are improved by rapid .DELTA.-Y connection switching by semiconductor switches (1, 2, 3, 4, 5), for example, TRIAC's.

Abstract: Provided is a spindle drive control apparatus which is provided with a single three-phase spindle motor (60) for rotatingly driving a spindle (50) of a machine tool and a solenoid relay (70) for switching the phase windings (U, V, W) of the motor between a delta (.DELTA.) and star (Y) state and which switches the phase windings to the delta connection when rotating the spindle (50) at high speed for heavy duty cutting work and switches to the star connection for generating the high torque when rotating at a superlow speed (for example, 0.5 rpm) for contouring machining work etc. In this way, it becomes possible to handle the machining work performed in the past with two types of motor by using just a single motor, thus contributing to reduced costs.

Abstract: When tapping is effected by a tap driven by a built-in spindle motor (12) and another motor (22), which built-in spindle motor directly drives the tap (14) to rotate without a transmission mechanism, and which other motor drives the tap (14) with the built-in spindle motor (12) to proceed along a longitudinal direction (Z), the two motors (12, 22) are synchronously controlled, and the difference between a commanded rotational speed output to the built-in spindle motor (12) from a synchronous control unit (36) and an actual rotational speed of the built-in spindle motor detected by a detector (16) is calculated by a difference calculator (32), and an alarm is output, for example, by a light-emitting diode (40), when the difference is higher than a prescribed value. Thereby, a high-speed tapping can be effected, the number of defective products can be reduced, and the threads accurately tapped.

Abstract: When a spindle (10) of a machine tool is rotated and moved relative to a workpiece linearly along an axis (Z) thereof during a machining process such as screw cutting, a spindle servomotor (12) and a feed servomotor (22), each of which is the primary drive, must be rotated synchronously. In general, the spindle servomotor directly drives the spindle without a reduction gear, and the feed servomotor feeds a spindle head (18) through reduction gears (26, 28). Therefore, in general, the synchronous work is controlled in accordance with an acceleration and deceleration capacity of the spindle servomotor. Consequently, the spindle servomotor is rotated along the torque limit curve line (L1, L2) to drive the spindle, to thereby effect the synchronous work at a high efficiency.