Abstract: An induction motor has a stator formed by inserting and holding piled steel plates (12) between end plates (11a, 11b) and welding support bars (13) consisting of nonmagnetic metal along the external surface of said piled steel plates.

Abstract: A motor-incorporated spindle head unit is provided with a rotatable spindle on which a rotor assembly of the drive motor is fixedly mounted. A stator assembly of the drive motor is arranged around the rotor assembly and is fixed to a housing of the spindle head unit. A heat insulating system for preventing heat transfer from the stator assembly of the drive motor to the spindle as well as the bearings supporting the spindle is arranged between the drive motor and the front part of the spindle. The heat insulating system uses the flow of air for forming a heat insulator during the operation of the spindle head unit. A cooling system for cooling the stator assembly of the drive motor is also incorporated in the housing of the spindle head unit.

Abstract: A stator of an electric motor comprises a laminated iron-core (1) having dovetail grooves, end plates (2) and steel bars (3) which are accommodated in the dovetail grooves and have a trapezoidal shape in cross-section. The steel bars (3) are arc-welded to the laminated iron-core (1) and to the end plates (2).

Abstract: A device for cooling a reversible motor comprising: a plurality of blade-type cooling fins (17) attached to the protrusion (13b) of a rotary shaft (13) which protrusion is protruded into a cooling chamber (5) formed on the outside of a motor case (10); an exhaust blower (25) provided on the outer side of the cooling chamber (5) in the axial direction to expel the cooling air, and; a fixed rectifying vane (29), consisting of a plurality of radially arrayed guide vanes (29a), provided in the exhaust space (28) between the blade-type cooling fins (17) and the exhaust blower. In the cooling device, the cooling air stream, moving in a spiral manner, passes through the blade-type cooling fins (17), is rectified in the axial direction via the fixed rectifying vane (29) and is expelled by the exhaust blower (25), when the motor runs in both the forward and the reverse directions.

Abstract: A direct current motor comprising: a yoke; an armature; a plurality of main magnetic poles equidistantly spaced around the inner circumference of the yoke, and each of which has a wide portion and a narrow portion, the air-gap between the armature and the main magnetic poles being narrow at the center and ends of the wide portion, and at the center of the narrow portion, and being wide at the intermediate of the wide portion, and at the ends of the narrow portion, and a plurality of interpoles, such as E-shaped interpoles, which are disposed at positions located between the adjacent narrow portions of the main magnetic poles.

Abstract: A rotary electric motor of a sealed type comprising a heat pipe in a rotor shaft and a plurality of air vents in a stator. In the operation of this motor, a rotor mounted on the rotor shaft is cooled by the heat pipe and simultaneously, the stator is cooled directly by the air flowing therethrough.

Abstract: A direct current motor having E-shaped interpoles, each of the E-shaped interpoles comprising interconnecting members which are made of a non-magnetic material having rigidity and which are tightly and irremovably inserted in gaps between a center pole and side poles of the E-shaped interpole. In the direct current motor according to the present invention, the side poles are mechanically interconnected to the center pole, so that noises generated by the vibration of the side poles are greatly reduced.

Abstract: A direct current motor used, for example, in a machine tool, comprising an armature, a plurality of main magnetic poles disposed around the armature having field windings wound thereon, and a plurality of E-shaped interpoles disposed at the intermediate position along the outer circumference of said armature between the adjacent main magnetic poles, each of the E-shaped interpoles consisting of a center pole to which an interpole winding is wound and two side poles, and the width of the gap between the outer circumference of the armature and the end surface of each of the side poles increases from the portion of the gap which is remote from the center pole to the portion of the gap which is adjacent to the center pole.In the DC motor according to the present invention, the linearity of the magnetic flux used for commutation is ensured in a wide range of the armature current, and, therefore, commutating characteristics of the E-shaped interpoles is improved.

Abstract: A direct current motor used, for example, in a machine tool, comprising an armature, n main magnetic poles disposed around the armature, each of the main magnetic poles consisting of a pole core on which a field winding is provided and a pole piece extending along the outer circumference of the armature, and n/2 E-shaped interpoles disposed at the intermediate position along the outer circumference of the armature between the adjacent main magnetic poles, and at the central axis of the armature, the angle spanning from the direct axis, which is electrically perpendicular to the interpole axis, to an end portion of a pole piece of a main magnetic pole is unequal to that from the direct axis to the other end portion of the pole piece of the main magnetic pole.Since the number of the E-shaped interpoles is decreased by half, the direct current motor according to the present invention has simple structure and high torque, and the heat generated by the interpoles is relatively decreased.

Abstract: An actual speed N of a DC motor and an armature current Ia are detected to detect the motor output N.times.Ia. The motor speed is changed so that the detected motor output may not exceed a predetermined value. The spark generation of the motor brush is prevented when an over load is applied to the motor.

Abstract: A rotary electric machine with a heat pipe for cooling, which pipe comprises a rotary shaft. The rotary shaft has a hole formed therein extending from a heating zone to a cooling zone and has working fluid charged therein. The inner diameter of the cooling zone is smaller than the diameter of the heating zone, and an inner wall of the cooling zone is connected to an inner wall of the heating zone via a step.

Abstract: A direct current motor having interpoles mounted therein. The motor comprises a circular-shaped yoke, two main magnetic poles equidistantly disposed inside of the yoke and with their polarities different from each other, an armature, having armature windings wound thereon, which is actuated by an electromotive force caused by the main magnetic poles and which is rotated in the magnetic field generated by the main magnetic poles, and interpoles which are disposed at positions located between the two main magnetic poles so as to face the armature windings. Each of the interpoles comprises three small poles which are disposed inside of the yoke and are magnetically insulated from the yoke. As a result of this construction magnetic circuits are formed between the adjacent two small poles of each interpole and the armature.

Abstract: Disclosed is a direct current motor which comprises an armature, provided with armature windings thereon, and a plurality of field magnet devices, each of the field magnet devices being divided into three parts along the rotational direction of the armature. The parts are a main pole, which consists of a permanent magnet or an electromagnet activated by field windings wound thereon and which is disposed at a central portion of the field magnet device, and a pair of auxiliary poles, each of which consists of a permanent magnet. One of the auxiliary poles is disposed at one end of the main pole and the other auxiliary pole is disposed at the other end of the main pole. The permeability of the auxiliary poles is selected to be smaller than that of the main pole, and the polarity of the auxiliary poles is selected to be the same as that of the main pole.

Abstract: A drive circuit for a DC motor provided with an armature having an armature winding and a plurality of field poles. The field poles are each composed of a main pole excited by a field winding and an auxiliary pole formed with a permanent magnet of the same polarity as the main pole. An armature current is shunted to supply a field current to the field winding connected in series to the armature. The field current remains zero until the armature current reaches a predetermined value, and increases with an increase in the armature current after the latter exceeds the predetermined value. As a result of this, in the region in which the armature current is small, that is, in the high-speed region of the motor, a torque larger than that of a DC series motor is obtained, and in the region in which the armature current is large, that is, in the low-speed region of the motor, a torque larger than that of a permanent magnet type DC motor is provided.

Abstract: A motor having a clutch device which can provide a desired one of two (or more) rotating speeds of a rotor of the motor, comprising: an armature which is rotated by a driving shaft of said rotor and is slidable along the axis thereof; two rotating drive members which are rotatably supported by said driving shaft; electromagnetic exciting members which can attract said armature to a desired one of said rotating drive members, wherein a desired one of said rotating drive members produces rotational power due to the rotation of said driving shaft via said armature.

Abstract: Disclosed herein is a machine tool consisting of a bed, a fast head stock mounted on the bed and a main spindle rotatably supported by the fast head stock, and wherein the main spindle is an integral part of an output shaft of an electric motor.

Abstract: A drilling machine with an automatic tool changer (A.T.C.) comprising a driving motor for a spindle head and a tool magazine rotatably supported by the spindle head and provided with a plurality of tool arbors for holding tools, one of the tools being interchanged with another of the tools by intermittent rotation of the tool magazine, and wherein the tool arbors are supported for swinging movement between a protrusion position and a retraction position so as not to obstruct the machining operation.